JSS 3 First Term

Learning Objectives

• Define a computer network and state why networks are used.
• Describe PAN, LAN, MAN and WAN by the area each covers.
• Explain how IP addresses and DNS help devices communicate.
• Apply rules of online safety and digital citizenship.

Starter Scenario

Three friends in the same classroom each have a document on their own phone. They want to share these documents with one another so that all three have all three documents. Two different ways they could share without using the internet include Bluetooth, sharing via a USB cable, a local Wi-Fi network, or passing the device round physically. Connecting devices together lets them share resources, and that is the heart of networking.

What is a Computer Network

A computer network is two or more computers or devices connected together so they can share resources such as files, printers, internet access and messages. Devices on a network are sometimes called nodes. Networks are set up for several reasons, including sharing files and folders, sharing hardware such as printers and scanners, sharing one internet connection, communicating through chat, email and video calls, and storing data centrally on a server. In a school setting, a network allows every student in the computer laboratory to use one printer, access shared folders on the server, and browse the internet through a single connection.

There are advantages to using a network. Resource sharing lets one printer be shared by many users, which saves money because the school does not need to buy a printer for every computer. Easy sharing of files between users means a teacher can place a document on a shared drive and every student can access it. Central storage means data can be stored on a server and accessed from any computer on the network. Fast communication allows users to message, email or video-call one another. Centralised security and backup protect data across all devices. A shared internet connection lets many users browse through one subscription.

There are also disadvantages and risks. If the network server breaks down, many users lose access at once. Networks can be attacked by hackers or viruses, creating a security risk. Equipment such as routers, switches, cables and servers is expensive to buy and maintain. Networks need skilled people to set up and manage them. Viruses can spread quickly from one device to another across the network.

Types of Networks

Networks are classified by the area they cover. A Personal Area Network, or PAN, is the smallest type, covering the space around one person. For example, when you connect a Bluetooth headset to your phone, you have created a PAN. A Local Area Network, or LAN, covers a limited area such as one building, school or office. A school computer laboratory where 30 computers share one printer and one internet connection is a typical LAN. A Metropolitan Area Network, or MAN, covers a city. For example, a university with campuses in different parts of Abuja might use a MAN to connect them. A Wide Area Network, or WAN, covers a very large area such as a country or the whole world. The internet itself is the largest WAN in existence.

The Internet and How it Works

The internet is a world-wide system of interconnected computer networks. It allows any device connected to it, whether computer, phone, tablet or smart TV, to send and receive information with any other connected device anywhere on Earth. Because it is a network of networks, the internet has no single owner. Many organisations and companies around the world help to keep it running. The internet supports many services, including the World Wide Web, email, messaging apps like WhatsApp and Telegram, video calls like Zoom and Google Meet, online games, streaming services like YouTube and Netflix, and cloud storage and online banking.

Many people confuse the internet with the World Wide Web, but they are different. The internet is the physical and logical network infrastructure that moves data. The World Wide Web is one service that runs on the internet, which lets us view web pages using a browser. An analogy is that the internet is like the network of roads and highways, while the World Wide Web is like the shops and buildings you visit along those roads. You need the roads, which represent the internet, to reach the shops, which represent websites.

When you visit a website, six steps happen in order. First, you type the address such as www.example.com into the browser. Second, the browser asks the DNS service to find the IP address of that server, like looking up a phone number in a directory. Third, your request is split into small pieces of data called packets. Fourth, the packets travel across many routers and networks until they reach the web server. Fifth, the server sends the web page back, also as packets. Sixth, your device reassembles the packets and displays the page. Every device has an IP address, like a home address, and the DNS works like a phonebook that matches website names to their addresses.

There are several means of accessing the internet. Fibre optics send data as light through thin glass cables at very high speed. Mobile broadband, including 3G, 4G and 5G, sends data via mobile phone networks using SIM cards and data plans from providers like MTN, Airtel, Glo and 9mobile. Satellite internet sends data to and from satellites in space, with providers like Starlink and VSAT. Wi-Fi lets a router broadcast internet into a local area wirelessly. Dial-up and DSL are older methods that use telephone lines.

Digital Citizenship and Online Safety

Digital citizenship means using technology responsibly, respectfully and safely. A good digital citizen respects other people online and uses polite language. A good digital citizen does not share other people's private information without permission and does not bully or harass others online. A good digital citizen respects copyright and does not steal other people's work. A good digital citizen uses strong passwords and keeps accounts secure. A good digital citizen thinks before posting, because what goes online stays online. A good digital citizen helps others stay safe.

Common online risks include phishing, which is a trick used to steal personal information by pretending to be a trusted person, such as a fake message saying you won a prize and asking you to click a link. Malware and viruses are harmful software designed to damage or steal data. Cyberbullying involves bullying using digital devices, such as sending mean messages to a classmate. Identity theft uses someone's personal details to impersonate them. Scams and fraud cheat people for money, such as fake online shops that never deliver. Inappropriate content includes harmful or unsuitable material. Stranger danger involves meeting or talking to strangers online who may not be who they claim to be.

To stay safe online, never share your passwords with anyone except your parents or guardian. Create strong passwords by mixing letters, numbers and symbols. Do not post your full name, address, phone number or school online. Do not accept friend requests or messages from strangers. Do not click suspicious links or open unknown attachments. Check before downloading apps or files and use official stores. Log out of shared computers and devices. Do not meet someone you met online in person without a trusted adult. Tell a parent or teacher immediately if something feels wrong online. Limit screen time and balance online time with offline activities.

Personal Online-Safety Plan

Every learner should draft a short personal plan with three parts. The first part is one rule you will follow for your password, such as never sharing it and changing it regularly. The second part is one type of personal information you will never share online, such as your home address or phone number. The third part is one action you will take if a stranger or scammer contacts you, such as blocking them and telling a trusted adult. This plan forms part of the JSS3 first-term project theme of using technology safely and responsibly.

Systems Diagnostic Activity

A school computer laboratory has 30 computers, one server and two printers. The lab wants all computers to share the printers, share files and access the internet, while keeping the students' accounts safe. The type of network best for this laboratory is a LAN. The device that should connect the lab to the outside internet is a router. The single resource that can be shared so only one printer is needed is the printer itself through hardware sharing. Central storage on a server is useful because files can be stored in one place and accessed by all. One online safety measure needed for the students' accounts is using strong passwords and not sharing them. If the server breaks, many users lose access at once, which is a disadvantage of networks.

Practical Work

1. List three ways two phones can share a file without using the internet.
2. Draw a table of the four network types and give one example of each.
3. State two advantages and two disadvantages of using a network.
4. Write a personal online-safety plan with three rules you will follow.

Scenario-Based Questions

1. A school in Abuja has 25 computers in one room and wants all of them to share a single printer. Should the school set up a PAN or a LAN? Explain your choice by comparing what each type covers.
2. Amina and Bola each have a document on their phones. They want to send the files to a third friend, Chidi, who is sitting right beside them. Which network type is best for this, and what technology would they most likely use?
3. Mr Odelami says the internet and the World Wide Web are not the same thing. A learner replies, But I use the internet to visit websites on the web. Write a short explanation that clarifies the difference.
4. A community centre installs fibre-optic internet but the cables are expensive. A nearby school on a tight budget wants internet access. Name two other ways to connect and say which one you would recommend for the school and why.
5. A new teacher opens a social media account and immediately posts the school address, her phone number, and a photo of the school compound. Identify two online safety mistakes the teacher made and explain how to fix each one.
6. A government office has 50 computers that all lost internet access at the same time. The ICT technician says the server is down. Explain why a single server failure can affect many users at once.
7. A pupil receives an email that looks like it is from his bank, asking him to click a link and enter his account number. Name the online trick being used and describe two steps the pupil should take before clicking.

Learning Objectives

• Explain what the internet is and the part an ISP plays.
• Describe IP addresses, URLs and the World Wide Web.
• Compare common web browsers and explain how a search engine works.
• Judge the trustworthiness of online information and search safely.

Starter Scenario

Chidi in Abuja sends a short birthday message to his cousin Amara in Lagos at exactly 9 o'clock in the morning. The message arrives on Amara's phone within one second, even though Lagos is over 600 kilometres away. How did the message travel so fast? The answer lies in the internet, a vast network of networks, and the Internet Service Providers that connect Chidi's phone to Amara's phone through routers, cables, satellites or fibre optics. The message is broken into tiny pieces, sent across many networks, and reassembled on Amara's device almost instantly.

The Internet and ISPs

The internet is a world-wide system of interconnected computer networks that allows billions of devices to exchange information. It is not owned by one person or one company. Instead, thousands of organisations, governments and companies around the world help keep it running. The internet supports many services, including the World Wide Web, email, instant messaging, video calls, online gaming, streaming, cloud storage, and online banking. When people say they are going online, they mean they are connecting to the internet to use one or more of these services.

An Internet Service Provider, or ISP, is a company that gives individuals and organisations access to the internet. Without ISPs, homes and schools would have no way to connect. In Nigeria, popular ISPs include MTN, Airtel, Glo, 9mobile and Starlink for satellite. Fibre broadband providers also serve major cities. Schools often subscribe to a business ISP plan that provides a reliable, high-speed connection. ISPs charge fees for their services, typically monthly or yearly. Different plans offer different speeds and data limits. A school that downloads many videos and files will need a faster, higher-data plan than a household that only browses the web.

IP Addresses

Every device that connects to the internet is assigned a unique number called an IP address. IP stands for Internet Protocol. The IP address works like a house address because it tells the network exactly where to send data. There are two versions of IP addresses in common use today. IPv4 uses four numbers separated by dots, such as 192.168.1.1, and each number can range from 0 to 255. IPv6 uses a much longer format with both letters and numbers. IPv6 was created because the world ran out of IPv4 addresses. Without a valid IP address, a device cannot send or receive data on the internet. Some devices share a public IP address while using private IP addresses internally.

URLs and the World Wide Web

A URL, which stands for Uniform Resource Locator, is the address of a specific page or file on the internet. Every web page, image, video and document online has its own unique URL. A typical URL has several parts. The protocol part specifies the rules used to transfer the page, usually http or https. The domain name is the main name of the website, such as www.school.edu.ng. The path is the specific location of the page within the site, such as /subjects/digital-technology. The letter s in https stands for secure, meaning the connection is encrypted so that data travelling between your device and the server cannot be easily intercepted.

The World Wide Web, or WWW, is a system of interlinked hypertext documents that are accessed through the internet. It was invented by Tim Berners-Lee in 1989 at CERN, a research organisation in Switzerland. When you visit a website, your browser sends a request to a web server, which responds by sending back the web page in a language called HTML. The browser then renders the HTML into the text, images and layout you see on screen. The World Wide Web is often confused with the internet. The internet is the network infrastructure, while the web is one of many services that run on it. Email, messaging apps, and online games also run on the internet but are not part of the web.

Web Browsers

A web browser is software that lets you access, retrieve and display content from the World Wide Web. When you click a link or type a URL, the browser handles the entire process of connecting to the server and displaying the page. Popular browsers include Google Chrome, which is made by Google and is the most popular browser with a wide range of extensions. Mozilla Firefox is made by the Mozilla Foundation and has a strong privacy focus. Microsoft Edge is made by Microsoft and is built into Windows, integrating with Microsoft services. Safari is made by Apple and is the default browser on iPhones, iPads and Macs. Browsers store your browsing history, which is a list of pages you have visited. Clearing your history regularly is a good safety habit, especially on shared devices.

Search Engines and Safe Searching

A search engine is a tool that finds and lists web pages related to a search query. Popular search engines include Google, Bing and Yahoo. When a learner types a query, the search engine does three things in rapid succession. First, it crawls, when software called spiders or bots visit web pages and read their content. Second, it indexes, when the information gathered is stored in a huge database called an index. Third, it ranks, when the engine checks its index and displays the most relevant results, ranked from most to least relevant. Search results often include sponsored links, or ads, at the top. These are paid placements and may not always be the most relevant or trustworthy result.

Learners should practise safe searching by using specific keywords rather than vague phrases to narrow results. They should look at the website address before clicking, noting that trusted sites often end in.edu,.gov or well-known.com or.org domains. They should check the date of the article or page, because outdated information may no longer be accurate. They should avoid clicking on the first result if it is marked as an ad, unless they are sure it is from a trusted source. They should use safe search filters to block inappropriate content. They should never enter personal information on a website they found through a search unless they are sure the site is legitimate. They should cross-check important facts by looking at two or three different sources. If a result looks suspicious or too good to be true, they should not click on it.

Not every search result is equally trustworthy. Learners should practise critical evaluation by asking the following questions. Who wrote or published the page, and are they an expert on the topic? What is the purpose of the page, to inform, to sell, or to persuade? Does the page contain spelling errors, strange formatting or excessive pop-ups? Can the information be confirmed by other reliable sources? Being able to judge the quality of information is a key digital literacy skill and is essential for safe and responsible internet use.

Practical Work

1. Write the parts of the URL www.school.edu.ng/subjects/ict and explain each part.
2. Name four web browsers and state one feature of each.
3. Describe the three steps a search engine follows: crawling, indexing and ranking.
4. Rewrite a vague search into a precise one using better keywords.

Scenario-Based Questions

1. Kemi wants to visit www.verifiednews.ng. Write down the four parts of this URL and explain what each part does.
2. Two ISPs in Abuja offer internet plans. ISP A gives 50 Mbps at 15,000 naira per month. ISP B gives 10 Mbps at 8,000 naira per month. A cybercafe owner needs fast internet for many customers. Which ISP should the owner choose and why?
3. A pupil types www.old-example.com into a browser and sees an error page saying the site cannot be reached. Give two possible reasons for this error.
4. Aisha searches for symptoms of malaria on a search engine. The first result is a sponsored ad selling herbal medicine, while the third result is from a hospital website. Explain how Aisha should decide which result to trust.
5. A school blocks students from visiting certain websites during class hours. Explain the role of a web browser in this scenario and name one way the school might block the sites.
6. A trader sends a link to his friend saying, Click this to win a free phone. The link leads to a page that asks for the friend's bank details. Name the type of online trick this is and explain how the friend can check whether the link is safe.
7. A pupil writes a search query using very general words like stuff about animals and gets thousands of unrelated results. Suggest two ways the pupil can improve the search to get more useful results.

Learning Objectives

• Describe LAN, MAN, WAN and PAN in detail.
• Identify network devices and state the function of each.
• Explain how data travels across a network in packets.
• State the benefits of networking in a school.

Starter Scenario

The principal also wants the school's Kuje campus and the Wuse campus in Abuja to share student records. These are two different networking challenges. What kinds of networks would solve each one? The laboratory challenge calls for a Local Area Network, or LAN, that covers one building. The two-campus challenge calls for a wider network, possibly a Metropolitan Area Network, or MAN, or a Wide Area Network, or WAN, depending on the distance and technology used.

Types of Networks in Detail

A computer network is a collection of two or more devices, such as computers, printers, servers and phones, connected together by cables or wireless signals so they can share resources and communicate. Networks can be as small as two phones connected by Bluetooth or as large as the internet connecting billions of devices worldwide. The size and purpose of the network determine its type.

A Local Area Network, or LAN, connects devices in a limited area such as a single room, a building, or a school campus. LANs are the most common type of network in schools and offices. Key features of a LAN include short distances between devices, high data transfer speeds, the use of Ethernet cables or Wi-Fi, and being owned and managed by one organisation. In a typical school LAN, computers in the laboratory connect to a central switch, which connects to a router that provides internet access. A server in the school may store shared files and student accounts.

A Metropolitan Area Network, or MAN, covers a larger area than a LAN but smaller than a WAN, typically spanning a city. For example, a university with campuses in different parts of Abuja might use a MAN to connect them. A Wide Area Network, or WAN, covers a very large area, such as a country or the entire world. The internet is the largest WAN in existence. Companies with offices in different countries often set up private WANs to share data securely. A Personal Area Network, or PAN, is even smaller than a LAN, covering only the space around one person, such as a phone connected to a smartwatch by Bluetooth.

Network Devices

A Network Interface Card, or NIC, is a hardware component that allows a device to connect to a network. Every computer has a NIC, either built into the motherboard or inserted as an expansion card. The NIC converts data into electrical signals for wired networks or radio waves for wireless networks. Without a NIC, a computer cannot join a network at all.

A switch connects devices within a single LAN and directs data to the correct destination. When a switch receives data, it reads the destination address and sends the data only to the intended device. This is faster, more efficient and more secure than a hub. A hub, by contrast, sends data to every connected device regardless of destination, creating unnecessary traffic. Because of this difference, switches have largely replaced hubs in modern networks.

A router forwards data between different networks. When a school's internal LAN needs to reach the internet, the router is the device that connects the two. A modem converts digital data into signals suitable for transmission over telephone lines, cable lines or fibre optic lines, and converts incoming signals back into digital data. An access point allows wireless devices such as phones and tablets to connect to a wired network using Wi-Fi. A server is a powerful computer that stores shared files, runs applications and provides services to other computers on the network. A firewall monitors and filters network traffic to protect against threats.

How Data Travels Across a Network

When data is sent across a network, it follows a series of steps. First, the sending device creates the data, such as a message, file or request. Second, the Network Interface Card converts the data into electrical, optical or radio signals. Third, the data is broken into smaller pieces called packets. Fourth, each packet is labelled with a source address, which is the sender, and a destination address, which is the receiver. Fifth, network devices such as switches and routers read the destination address and forward the packet along the best path. Sixth, when all packets arrive at the destination, they are reassembled into the original message. This process happens in milliseconds and is repeated billions of times every second across networks around the world.

Benefits of Networking

Resource sharing allows one printer, scanner or internet connection to serve many users, reducing cost. Centralised data storage on a server makes files accessible to all authorised users from any device on the network. Fast communication through email, instant messaging and video calls improves collaboration between teachers and learners. Shared software licences reduce the need to install expensive programs on every individual computer. Networked security tools such as firewalls and antivirus software protect all connected devices from threats. Cloud backup and disaster recovery become possible when devices are connected to a reliable network. Networks enable online learning platforms, giving learners access to resources beyond the classroom.

Network Hardware Architectures and Network Terms

The way a network is organised is called its architecture. The two main architectures are client-server and peer-to-peer. In a client-server network, one powerful computer called the server stores files, runs software and shares resources, while the other computers, called clients, request those services. For example, a school laboratory server holds the shared project files and every learner's computer asks the server when it needs a document or a printer.

In a peer-to-peer network, all computers are equal. Every machine can both send and receive files directly to and from the others, with no central server. This architecture works well for small groups such as two or three friends sharing homework files at home, but it becomes harder to manage as the number of computers grows.

Every network also has common terms. A sender is the device that starts a message, a receiver is the device that gets it, the medium is the path the data travels on (a copper cable, a fibre-optic line or radio waves), and a node is any device connected to the network, such as a computer, printer or phone.

Client-server: one server serves many clients; used by banks, schools and offices.

Peer-to-peer: computers share directly without a central server; good for small home networks.

Sender: the device that starts the message.

Receiver: the device that receives the message.

Medium: the cable or wireless signal that carries the data.

Node: any connected device, including printers and phones.

Network Interconnection Devices in Detail

Devices that join different parts of a network together are called interconnection devices. A hub is the simplest. It connects several computers, but when data arrives it sends a copy to every device on the network, which wastes traffic. A switch improves on the hub by reading the destination address and sending data only to the intended computer.

A router connects two or more different networks and chooses the best path for data to travel, which is why a home router joins the local Wi-Fi network to the internet supplied by a provider such as MTN, Glo or Airtel. A modem (short for modulator-demodulator) changes digital signals from the computer into signals that can travel over telephone or cable lines and back again, giving the router its internet connection.

Longer networks need extra help. A repeater receives a weakening signal, strengthens it and sends it onward so that data can travel a longer distance without fading. A bridge connects two separate parts of the same network and only forwards data that is meant for the other side, which reduces unnecessary traffic.

A gateway is the doorway between networks that use different rules, for example a school LAN connecting to the wider internet. In many small networks the router, modem and gateway are combined in a single box. Each interconnection device has a distinct role, as the list below shows.

Hub: connects devices and broadcasts data to every device.

Switch: connects devices and sends data only to the correct device.

Router: joins different networks and routes data between them.

Modem: converts signals between the computer and the internet line.

Repeater: boosts a weakening signal over long distances.

Bridge: joins two parts of the same network and filters traffic.

Gateway: translates between networks that use different rules.

Core Internet Protocols and Addressing

Networks send data using agreed sets of rules called protocols. The most important family is TCP/IP. TCP (Transmission Control Protocol) breaks data into packets, numbers them and reassembles them at the destination, while IP (Internet Protocol) labels each packet with the sender's and receiver's internet addresses so it can be routed across the world.

Application protocols carry the everyday services. HTTP and its secure version HTTPS move web pages between servers and browsers, and HTTPS encrypts the exchange to protect data such as passwords and bank details. FTP (File Transfer Protocol) uploads and downloads files. SMTP (Simple Mail Transfer Protocol) sends email messages between mail servers.

People cannot easily remember long numeric addresses, so the Domain Name System (DNS) acts as the address book of the internet. It translates a name such as www.schoolname.ng into its numeric IP address. The current address system, IPv4, uses addresses such as 192.168.1.1, and the newer IPv6 uses much longer addresses to provide room for billions more devices. Every network device also carries a unique hardware label, its MAC address, which identifies the device on a local network.

TCP/IP: the rule family that fragments, addresses and reassembles data packets.

HTTP and HTTPS: rules for moving web pages; HTTPS adds encryption.

FTP: transfers files between computers.

SMTP: sends email messages between mail servers.

DNS: changes names like www.schoolname.ng into IP addresses.

IPv4 and IPv6: internet address systems; IPv6 is newer and larger.

MAC address: the unique hardware address of each network device.

Practical Work

1. Draw a simple school LAN showing computers, a switch and a router.
2. Make a table comparing LAN, MAN and WAN by area, speed and cost.
3. List the steps by which data travels from one computer to another.
4. List four benefits of networking a school computer laboratory.

Scenario-Based Questions

1. What type of network should the school set up, and what two devices does it need to connect the computers to each other and to the internet?
2. A small printing press has offices in Ikeja and in Victoria Island, both in Lagos. The two offices need to share files daily. What type of network connects them, and how does it differ from a LAN?
3. A bank in Abuja connects branches in Kano, Port Harcourt and Enugu. What type of network is this, and what is one advantage and one limitation compared to a LAN?
4. In a computer lab, a switch receives a data packet addressed to Computer 15. Explain how the switch ensures the packet reaches Computer 15 and not the other 29 computers.
5. A school replaces its old hub with a new switch. A teacher asks why the switch is better. Give two reasons by comparing how a hub and a switch handle incoming data.
6. A small business owner wants to share one internet connection, one printer and one scanner among five staff computers. List the minimum network devices needed and explain the function of each.
7. Two schools in the same street each have their own LAN. They want to share a single high-speed internet link. What device do they need to connect the two LANs together, and what type of network would the combined setup form?

Learning Objectives

• Describe the network interface card and the MAC address.
• Compare a hub, a switch and a router.
• State the role of the main internet protocols.
• Trace how a typed web address becomes a displayed page.

Starter Scenario

The ICT teacher brings a small circuit board to class and says, 'Without this tiny card inside every computer, no computer could join a network, no matter how many cables or routers you have.' The card is a Network Interface Card, or NIC. It is the essential hardware component that enables a device to connect to a network. Without a NIC, even the fastest router and the best internet connection would be useless, because the computer would have no means to send or receive data.

Network Devices in Depth

A Network Interface Card, or NIC, is a hardware component, either built into the motherboard or inserted as an expansion card, that allows a device to connect to a network. Every NIC has a unique address called a MAC address, which stands for Media Access Control address, and this identifies the device on the network. When a computer sends data, the NIC converts the data into electrical signals for wired networks or radio waves for wireless networks and places them on the network cable or airwaves.

A hub and a switch both connect multiple devices, but they work differently. When a hub receives data, it sends a copy to every connected device, even if the data is only meant for one device. This creates unnecessary traffic and reduces efficiency. When a switch receives data, it reads the destination address and sends the data only to the intended device. This is faster, more efficient and more secure. Because of this difference, switches have largely replaced hubs in modern networks. In a school laboratory, a switch would connect 30 computers and ensure each one receives only the data meant for it.

A router reads the destination IP address and forwards data between different networks. It is more intelligent than a switch because it decides the best path for data to travel across multiple networks. A modem converts digital data from a computer or router into a format suitable for transmission over telephone lines, cable lines or fibre optic lines. It also converts incoming signals back into digital data. The word modem comes from modulator-demodulator. An access point allows wireless devices such as phones, tablets and laptops to connect to a wired network using Wi-Fi. Without an access point, wireless devices cannot join the school's LAN. In many home and school setups, the modem, router and access point are combined into one device, but they perform three different functions.

Network Protocols

Two students in the same classroom speak different languages. One speaks only English and the other speaks only Hausa. Without a common language, they cannot communicate. Networks face the same problem when devices from different manufacturers, countries and operating systems need to talk to one another. The solution is a protocol, a set of rules that all devices agree to follow. Just as speakers of different languages can communicate through a shared language or translator, devices on a network communicate through shared protocols that define how data is formatted, addressed and transmitted.

A protocol is a set of rules and standards that govern how data is formatted, transmitted, and received across a network. Protocols ensure that devices from different manufacturers and running different software can communicate reliably. Without protocols, network communication would be chaotic. One device might send data too fast, another might not understand the format, and a third might not know where to send the response. Protocols solve all of these problems.

TCP/IP

TCP/IP stands for Transmission Control Protocol and Internet Protocol. It is the set of core protocols that makes the internet work. TCP/IP is actually two protocols working together. IP, the Internet Protocol, is responsible for addressing and routing packets. It assigns each device an IP address and ensures packets are sent to the correct destination across multiple networks. TCP, the Transmission Control Protocol, is responsible for reliability. It breaks data into packets, numbers them, sends them, and checks that all packets arrive correctly. If any packet is lost, TCP requests retransmission. Together, TCP and IP ensure that data reaches the right place, in the right order, without errors. Every web page, email, video call and file download relies on TCP/IP.

IPv4 means the older internet address system with four numbers.

HTTP and HTTPS

HTTP, which stands for HyperText Transfer Protocol, is the protocol used by web browsers to request and receive web pages from web servers. When you type a URL and press Enter, your browser sends an HTTP request to the server, which responds with the web page. HTTPS, which stands for HyperText Transfer Protocol Secure, is the secure version of HTTP. It adds encryption, meaning the data between your browser and the server is scrambled so that third parties cannot read it. HTTPS is essential for any activity that involves personal data, such as logging into accounts, online banking, or entering personal information. Websites that use HTTPS show a padlock icon in the browser address bar.

DNS and Putting It All Together

DNS stands for Domain Name System. When you type a domain name into your browser, your browser first checks its own cache to see if it already knows the IP address for that domain. If not found, the request goes to your operating system's cache. If still not found, the request is sent to a DNS resolver, usually provided by your ISP. The DNS resolver queries a series of DNS servers in order, first the root server, then the top-level domain server such as.com or.ng or.edu, and finally the authoritative name server for that domain. The authoritative server returns the correct IP address to the resolver. The resolver sends the IP address back to your browser, which then connects to the web server and loads the page. This entire process typically takes less than one second, even though it may involve several servers across different countries.

Consider a complete scenario. Amina in Abuja types www.news.ng into her Chrome browser and presses Enter. Amina's NIC sends the request as a signal through the school's network cable to the switch. The switch forwards the request to the school's router. The router sends the request to the ISP via the modem. The ISP's DNS resolver finds the IP address for www.news.ng using DNS protocols. The request, formatted as an HTTPS request using TCP/IP, travels across multiple networks to the news.ng web server. The server responds with the web page, encrypted using HTTPS. The packets travel back through the same chain, reassembled by TCP, and the browser displays the page. Every device and every protocol plays a specific role in this journey.

The Digital Economy: Old Ways versus New Ways

Before the internet, buying and selling happened mostly in physical markets, shops and offices with cash payments, printed receipts and paper records. The digital economy changed this by letting people buy, sell and transact through computers and phones connected to networks. E-commerce (buying and selling online) lets a customer order goods on a marketplace such as Jumia or Konga from anywhere in Nigeria, and online services include internet banking, airtime top-up and e-learning platforms. These services depend on the network devices and protocols studied this week.

Old economy: physical shops, cash payments and paper records.

New economy: online marketplaces, mobile transfers and electronic receipts.

E-commerce platforms such as Jumia and Konga connect buyers and sellers online.

Digital Literacy and Responsible Digital Citizenship

Digital literacy is the ability to find, evaluate, create and communicate information using digital tools. It includes searching the web effectively, judging whether a source is trustworthy and protecting personal information. Responsible digital citizenship means using technology safely and respectfully, such as not sending hurtful messages, not sharing false information and keeping passwords private. In Nigeria, the NDPR protects personal data, so learners should think before sharing sensitive details online.

Compare at least two sources before trusting online information.

Keep passwords private and never share them.

Avoid cyberbullying and report harmful messages.

Respect the NDPR by handling personal data carefully.

Intellectual Property, Copyright and Respecting Creative Work Online

Intellectual property is a creation of the mind with value, such as a song, a film, a book, a photograph or a software program. Copyright is the legal protection that gives the creator control over how their work is copied and shared. In Nigeria, the Nigerian Copyright Commission enforces these rights. Copying or downloading protected work without permission is piracy, while citing the source when quoting a writer or artist shows respect. Learners should always submit their own work and credit any borrowed ideas.

Intellectual property covers songs, films, books, photos and software.

Copyright gives the creator control over copying and sharing.

Piracy, copying protected work without permission, breaks the law.

Cite sources when quoting the work of another person.

Practical Work

1. Write one sentence on what each of the NIC, hub, switch, router and modem does.
2. Draw a table comparing HTTP and HTTPS.
3. List the steps a browser takes to load a named website.
4. Explain, using an example, why a switch is better than a hub.

Scenario-Based Questions

1. A school buys a new desktop computer. The ICT teacher says it cannot join the network without a NIC. What is a NIC, where is it located inside the computer, and what does it do?
2. A cybercafe has 20 computers connected by a hub. Customers complain that the network is slow. Explain why a hub causes delays when many computers send data at the same time, and suggest a better device to replace the hub.
3. Amina types www.news.ng into her browser. Trace the full journey of how her browser turns this name into data she can read, naming at least three devices or services involved.
4. A government office sends secret reports over the internet. The ICT officer insists on using HTTPS instead of HTTP. Explain the difference between the two and why it matters for secret documents.
5. A school network has a router, a switch and a modem. A new teacher asks what each device does. Explain the role of each device in one sentence.
6. A data packet leaves Computer A in one building and must reach Computer B in another building on a different network. Describe the role of the router in getting this packet to its destination.
7. A pupil says DNS is the same as IP address. Write a short correction explaining what DNS does and what an IP address does, and why both are needed.

Learning Objectives

• Explain place value in the decimal and binary systems.
• Convert numbers between decimal, binary and hexadecimal.
• Describe the octal system and what it is used for.
• Explain why computers use the binary system.

Starter Scenario

Amina's younger brother asks her, how does a computer count, it does not have fingers like we do. Amina thinks about her ten fingers and the decimal system she uses for counting, then wonders how a machine with only electrical signals can represent numbers at all. Computers use electric circuits that are either on or off, much like a light switch. An on state can represent 1 and an off state can represent 0. Using only these two digits, computers represent every number, letter, picture and sound. This is the binary system.

What is a Number System

A number system is a way of representing numbers using a specific base and a set of digits. The base of a number system tells you how many distinct digits it uses and how the value of each position increases. Every number system works on the same principle of place value. In the decimal system we use every day, each position from right to left multiplies by 10 because the decimal system has a base of 10.

The decimal system is base 10, meaning it uses ten digits from 0 to 9. Each position in a decimal number represents a power of 10. The positions from right to left are ones, which is 10 to the power 0, tens, which is 10 to the power 1, hundreds, which is 10 to the power 2, thousands, which is 10 to the power 3, and so on. Consider the number 2473. The digit 3 is in the units position with a place value of 1, giving 3 times 1 equals 3. The digit 7 is in the tens position with a place value of 10, giving 7 times 10 equals 70. The digit 4 is in the hundreds position with a place value of 100, giving 4 times 100 equals 400. The digit 2 is in the thousands position with a place value of 1000, giving 2 times 1000 equals 2000. Then 2473 equals 2000 plus 400 plus 70 plus 3. This same principle of place value applies to every number system, but the base changes.

The Binary System

The binary system is base 2, using only two digits, 0 and 1. Each position in a binary number represents a power of 2. The positions from right to left are ones, which is 2 to the power 0, twos, which is 2 to the power 1, fours, which is 2 to the power 2, eights, which is 2 to the power 3, sixteens, which is 2 to the power 4, and so on. Consider the binary number 1101. The digit 1 is in the ones position with a place value of 1, giving 1 times 1 equals 1. The digit 0 is in the twos position with a place value of 2, giving 0 times 2 equals 0. The digit 1 is in the fours position with a place value of 4, giving 1 times 4 equals 4. The digit 1 is in the eights position with a place value of 8, giving 1 times 8 equals 8. Then binary 1101 equals 8 plus 4 plus 0 plus 1, which is 13 in decimal.

Converting Decimal to Binary

To convert a decimal number to binary, repeatedly divide by 2 and record the remainders. The remainders, read from bottom to top, give the binary number. For example, to convert 13 to binary, first divide 13 by 2 to get 6 with remainder 1. Then divide 6 by 2 to get 3 with remainder 0. Then divide 3 by 2 to get 1 with remainder 1. Then divide 1 by 2 to get 0 with remainder 1. Reading the remainders from bottom to top gives 1101. So decimal 13 equals binary 1101. Learners can verify this by converting back, since 1101 equals 8 plus 4 plus 0 plus 1, which is 13.

The Octal System

The octal system is base 8, using digits from 0 to 7. Each position represents a power of 8. The positions are ones, which is 8 to the power 0, eights, which is 8 to the power 1, sixty-fours, which is 8 to the power 2, and so on. Octal is useful because every three binary digits can be grouped into one octal digit. This makes long binary numbers easier to read. For example, binary 000 equals octal 0, binary 001 equals octal 1, binary 010 equals octal 2, and so on up to binary 111 equals octal 7. To convert a binary number to octal, group the binary digits in threes from the right, then replace each group with its octal equivalent.

The Hexadecimal System

The hexadecimal system, often called hex, is base 16, using the digits 0 to 9 and the letters A, B, C, D, E and F. The letters stand for the decimal values 10, 11, 12, 13, 14 and 15. Every four binary digits map to exactly one hexadecimal digit, making binary strings much shorter and easier to read. For example, binary 0000 equals hex 0, binary 0001 equals hex 1, and so on through binary 1001 equals hex 9, binary 1010 equals hex A, binary 1011 equals hex B, binary 1100 equals hex C, binary 1101 equals hex D, binary 1110 equals hex E, and binary 1111 equals hex F.

Converting Between Systems

There are three main conversion directions learners should master. To convert binary to decimal, multiply each binary digit by its place value and add the results. For example, binary 1101 equals (1 times 8) plus (1 times 4) plus (0 times 2) plus (1 times 1), which equals 8 plus 4 plus 0 plus 1, which is 13. To convert decimal to binary, repeatedly divide by 2 and read remainders from bottom to top. For example, decimal 13 equals binary 1101. To convert binary to hexadecimal, group in fours from the right and replace each group. For example, binary 10110101 grouped as 1011 and 0101 equals B5 in hexadecimal.

Practical Work

1. Write the place values of the binary number 1101 and convert it to decimal.
2. Convert the decimal number 13 to binary by repeated division.
3. Convert the binary number 10110101 to hexadecimal.
4. Write the hexadecimal digits and their decimal values from 0 to F.

Scenario-Based Questions

1. A computer stores the number 1011 in binary. A pupil says this is the same as one thousand and eleven in decimal. Convert 1011 from binary to decimal to show the pupil the correct answer.
2. A school wants to label 16 network cables from 0 to 15 using hexadecimal numbers. Write out the 16 labels and explain why hexadecimal is shorter than using binary for the same labels.
3. A market trader counts her goods in tens and ones, for example 23 means 2 tens and 3 ones. Explain how this is like positional value in the decimal system and how binary uses the same idea with only 0 and 1.
4. A pupil converts the decimal number 13 to binary by dividing by 2 and gets 1101. Write out the step-by-step division showing the remainders to prove the answer is correct.
5. A radio station uses the number C4 in hexadecimal to label a frequency channel. Convert C4 to decimal and then to binary.
6. A teacher writes the number 77 on the board and asks the class to convert it to binary and to hexadecimal. Show both conversions.
7. Explain why computers use binary instead of decimal, linking your answer to the electrical state of a circuit.

Learning Objectives

• Distinguish between a bit, a byte and a word.
• Convert between binary and decimal using place value.
• Explain how text, images and sound are stored in binary.
• Use the units of data such as the kilobyte and the megabyte.

Starter Scenario

A market trader uses a simple tally sheet with only two marks, a plain tick and a crossed tick, to count her sold crates each day. With just these two symbols she can record any total, because the position of each mark gives it a value. Computers do something similar, but with only two digits. Instead of many symbols, a computer uses just two states, which we write as 0 and 1. This two symbol system is called binary, and it is the language of all digital devices.

Bits and Bytes

A bit is the smallest piece of data a computer can handle. The word bit comes from binary digit, and a bit is always either 0 or 1. Because one bit only carries two possibilities, computers group bits together. Eight bits make one byte. A byte is enough to hold one letter of text, and modern files are described in bytes, kilobytes, megabytes and gigabytes. Think of a bit as one light switch that is either off or on. A single switch shows only two states, but many switches together can show an enormous number of combinations.

Our everyday numbers are in the decimal system, which is base 10, because it uses ten digits from 0 to 9. Each position in a decimal number is worth ten times the position to its right, so 10, 100 and 1000 are place values. The binary system is base 2, because it uses only two digits, 0 and 1. Each position is worth two times the position to its right, so the place values are 1, 2, 4, 8, 16 and so on. Computers use binary because their circuits have two clear states, such as on or off, high or low voltage, and magnetised or not magnetised. Using two states is simple and reliable for electronics.

Reading Binary Place Values

To understand a binary number, write its place values above the digits from the right. The rightmost position is worth 1, the next is 2, then 4, then 8. Take the binary number 1011. Above it from the right we place 1, 2, 4 and 8. So 1011 means one eight, zero fours, one two and one one, which is 8 plus 2 plus 1, giving decimal 11. To convert this binary to decimal, only add the place values that sit above a 1, giving 8 plus 2 plus 1, which equals 11.

Converting Between Binary and Decimal

To convert binary to decimal, write the binary digits, then label the place values 1, 2, 4, 8 and 16 from right to left. Add only the labels that sit above a 1, and the total is the decimal number. For example, binary 10101 has place values 16, 8, 4, 2 and 1 from left to right. The 1s sit above 16, 4 and 1, so the value is 16 plus 4 plus 1, which is 21.

To convert decimal to binary, find the largest binary place value that fits inside the decimal number, put a 1 there, then subtract. Repeat with the remainder using the next smaller place value, putting a 0 where a place is not used, until you reach the 1s column. For example, to turn 13 into binary, the largest place that fits is 8, so we put a 1 and subtract to get 5. The next place, 4, fits, so we put a 1 and subtract to get 1. The 2s place does not fit, so we put a 0. The 1s place fits, so we put a 1. Reading across we get 1101.

How Text is Stored

Each letter, digit and symbol on a keyboard is given a code number. One common system is ASCII, in which a capital A is 65, a capital B is 66, and so on, and each number is then written in binary. Because a byte has eight bits, it can hold any code from 0 to 255, which is enough for all letters, digits, punctuation and symbols. When you type a word, the computer stores the code of each character one after another, and each character takes about one byte. For example, the word OK would be stored as the code for O, which is 79, and the code for K, which is 75, each written in eight bits.

How Images are Stored

An image on a screen is made of tiny dots called pixels, arranged in rows and columns. Each pixel records a colour, and each colour is stored as a number in binary. In a simple black and white image, a pixel can be a 0 for black and a 1 for white. In a colour image, each pixel keeps separate numbers for the amount of red, green and blue, and those numbers are also stored in binary. The more pixels an image has, the sharper it looks, but the more 0s and 1s it needs, which is why photo files can be large.

How Sound is Stored

Sound is a moving wave in the air. A computer records sound by measuring the wave many times each second and turning each measurement into a number. These measurements are called samples. Each sample is stored in binary, and by replaying the samples in order the device rebuilds the original sound. Recording more samples per second gives better quality but uses more data. So whether the device works with a typed letter, a colourful photo or a recorded song, the process is the same. Everything is turned into numbers, and those numbers are written in binary.

Reading a Simple Binary Message

Using a small code where A equals 1, B equals 2, and so on, each letter can be written in binary and read back by a decoder. For example, A equals 1 in decimal and 1 in binary. B equals 2 in decimal and 10 in binary. C equals 3 in decimal and 11 in binary. D equals 4 in decimal and 100 in binary. Learners should decode the binary message 100, 1, 11, 4 by converting each binary back to decimal and then to a letter to read the hidden word.

Binary Data Representation

Computers store all information using only two digits, 0 and 1. This is the binary system, and every piece of data a computer handles, whether it is a letter, a photograph or a song, is ultimately represented as a long sequence of these two digits. The reason computers rely on binary is that electronic circuits have two clear states such as on and off, high voltage and low voltage, which map perfectly to 1 and 0.

A bit is the smallest unit of data in a computer. The word bit is short for binary digit, and it can hold only one of two values, either 0 or 1. Because a single bit carries so little information, computers group bits together into larger units. A byte is the most common grouping and it consists of exactly eight bits. Eight bits give 256 possible combinations (from 00000000 to 11111111), which is enough to represent one character of text or a small number.

Beyond the byte, computers use words, which are groups of bits that the processor handles in one operation. On a 32-bit computer, a word is 32 bits (four bytes), and on a 64-bit computer, a word is 64 bits (eight bytes). The size of the word affects how fast the computer can process data because a larger word means more data is handled in a single step.

A bit holds a single 0 or 1 and is the fundamental building block of all digital data.

A byte contains eight bits and is the standard unit for measuring data size.

A word is the number of bits a CPU processes in one cycle, commonly 32 or 64 bits on modern computers.

All data inside a computer, including text, images, sound and programmes, is stored as sequences of 0s and 1s.

Storage Metrics and Simple Conversions

Data in a computer is measured using a standard set of units that grow from the very smallest to very large. A bit is the smallest unit, representing a single 0 or 1. Two bits together can represent four different values (00, 01, 10, 11), and four bits form a nibble, which can represent sixteen different values. A nibble is half a byte and is sometimes used when working with hexadecimal numbers.

A byte, made up of eight bits, is the most commonly used unit. One byte can represent 256 different values, which is enough for a single character in many encoding systems. When we need to describe larger amounts of data, we use multiples of bytes. A kilobyte (KB) is 1,024 bytes, a megabyte (MB) is 1,024 kilobytes, a gigabyte (GB) is 1,024 megabytes, and a terabyte (TB) is 1,024 gigabytes. The number 1,024 is used because computers work in binary and 1,024 is 2 to the power of 10.

Understanding these units helps when choosing storage or comparing devices. A typical school essay might be 50 KB, a photograph around 3 MB, a short video clip about 100 MB, and a full-length movie around 4 GB. Internet speeds are often measured in megabits per second (Mbps), while file sizes are usually shown in megabytes (MB). There are eight bits in a byte, so a speed of 8 Mbps can transfer roughly 1 MB of data each second.

1 bit = a single 0 or 1.

4 bits = 1 nibble = 16 possible values.

8 bits = 1 byte = 256 possible values.

1 KB = 1,024 bytes. 1 MB = 1,024 KB. 1 GB = 1,024 MB. 1 TB = 1,024 GB.

Character Encoding, ASCII and Unicode

For a computer to store and display text, every character must first be converted into a number, and that number is then stored in binary. Character encoding is the system that assigns a unique number to each letter, digit, punctuation mark and special symbol. One of the earliest and most well-known encoding systems is ASCII, which stands for American Standard Code for Information Interchange.

The original ASCII system uses seven bits to represent each character, giving 128 possible codes (from 0 to 127). This is enough for all uppercase and lowercase English letters, the digits 0 to 9, common punctuation marks and control characters such as space and line break. For example, the letter A is assigned the code 65, the letter a is 97, and the digit 0 is 48. An extended version of ASCII uses eight bits (one byte), which doubles the available codes to 256, allowing room for additional symbols used in European languages.

As computers spread worldwide, ASCII proved limited because it could not represent characters from languages such as Arabic, Chinese, Hindi or Yoruba. Unicode was created to solve this problem. Unicode assigns a unique code to every character in every writing system, including emojis and mathematical symbols. The most common form of Unicode is UTF-8, which uses one to four bytes per character. UTF-8 is backward compatible with ASCII, meaning that the code for A is still 65, but Unicode can also represent characters far beyond the original 128.

ASCII assigns a 7-bit code (0 to 127) to English letters, digits and common symbols.

Extended ASCII uses 8 bits and supports 256 characters, useful for European languages.

Unicode supports characters from all the world writing systems and uses 1 to 4 bytes per character.

UTF-8 is the most widely used encoding on the internet because it handles both ASCII and non-ASCII characters efficiently.

Character encoding matters because without a shared standard, different computers would interpret the same binary numbers as different characters, leading to garbled text.

Practical Work

1. Convert the binary number 10101 to decimal.
2. Write the codes 65 and 66 in binary to represent A and B.
3. Estimate the size of a photograph in megabytes from its pixels.
4. Decode the binary message 100, 1, 11, 4 using A equals 1.

Scenario-Based Questions

1. A pupil says one byte is the same as one bit. Correct this by explaining the difference between a bit and a byte and giving one example of how many of each is needed to store the letter A.
2. A school asks how much memory is needed to store 200 characters if each character uses 8 bits. Show your working.
3. A market trader uses a tally where a tick means 1 and a crossed tick means 0, just like binary. If the trader writes tick, crossed tick, tick, tick, what decimal number does this represent?
4. A phone camera takes a photo that is 1920 pixels wide and 1080 pixels high. If each pixel uses 3 bytes for colour, estimate the total size of the photo in megabytes.
5. Using ASCII where A equals 65, write the letter A in binary and explain how a computer stores the word CAT.
6. A song is recorded for 60 seconds at a sampling rate of 44,100 samples per second, with each sample using 16 bits. Estimate the size of the recording in megabytes.
7. A school lab has computers that store text in ASCII. A pupil types the word NAIJA. How many bytes are needed to store this word, and how would the computer store the letter N in binary?

Learning Objectives

• Explain what a logic gate is and how it uses bits.
• State the rule of the AND, OR and NOT gates.
• Draw truth tables for the basic gates.
• Describe how gates are combined in a computer.

Starter Scenario

A school laboratory will only let a computer start when two conditions are both true, the door key card is inserted and the power switch is on. If either one is missing, the computer stays off. This is a real world AND decision, because both conditions must be true together. In a computer, a small circuit called an AND gate makes exactly this kind of choice.

What is a Logic Gate

A logic gate is a small electronic circuit that takes one or more inputs, each being 0 or 1, and gives a single output, also 0 or 1. Because every part of a computer stores data as bits, gates are the building blocks that move and combine those bits. The three basic gates are AND, OR and NOT. Each follows a fixed rule, no matter what it is connected to, and its rule can be shown in a truth table. Computers contain millions of gates packed onto a tiny silicon chip, and by combining many gates the computer can add numbers, compare values and follow instructions.

The AND Gate

An AND gate has two inputs and one output. Its rule is simple. The output is 1 only when both inputs are 1. In any other case the output is 0. The AND rule is like two switches in one room light circuit. The bulb lights, giving output 1, only when both switches are on, because the electricity must pass through both. The truth table for an AND gate shows four rows for all possible input combinations. When both inputs are 0, the output is 0. When input A is 0 and input B is 1, the output is 0. When input A is 1 and input B is 0, the output is 0. When both inputs are 1, the output is 1.

Everyday AND decisions include taking your book home only if it is at school and it is your book. A bus departs only when all passengers are seated and the door is closed. You hand in your drawing only when it is finished and your name is on it. In each example both conditions must be true at once, which is exactly what an AND gate checks.

The OR Gate

An OR gate has two inputs and one output. Its rule is that the output is 1 when at least one of the inputs is 1. The output is 0 only when both inputs are 0. The OR gate is like two switches joined in parallel, where either switch on its own completes the path and lights the bulb. The truth table for an OR gate shows that when both inputs are 0 the output is 0. When input A is 0 and input B is 1, the output is 1. When input A is 1 and input B is 0, the output is 1. When both inputs are 1, the output is 1.

Everyday OR decisions include entering the park if you have a ticket or a staff card. A pupil stays for the club if it is raining or if her ride is late. You can pay with cash or with transfer at the market stall. In each case only one true condition is enough, which is the heart of the OR gate.

The NOT Gate

A NOT gate has only one input and one output. Its rule is to flip the value, so a 0 becomes 1 and a 1 becomes 0. It is sometimes called an inverter. The NOT gate is like a light that is on when the switch is off, and off when the switch is on, always showing the opposite of what you expect. The truth table for a NOT gate has just two rows. When the input is 0, the output is 1. When the input is 1, the output is 0.

How Gates Combine Inside a Computer

When the output of one gate feeds into the input of the next, the gates work in a chain. You can trace a signal through the chain, deciding the value at each step using the truth tables. For example, take the output of an AND gate and feed it into a NOT gate. If the AND gives 1, the NOT then gives 0, and if the AND gives 0, the NOT gives 1. The combined circuit gives the opposite of the AND result.

Gates are built into the processor chip, the memory and many other parts of a computer. Their tiny size lets millions of them fit on one chip, and the speed of their switching controls how fast the computer works. Addition is a good example. A simple binary adder is made by connecting a few AND, OR and NOT gates, and the same gate building blocks appear again and again in circuits that compare numbers, follow rules and store values. For learners, the key idea is that there is no magic in a computer, only many simple gates arranged in clever ways to make bigger decisions.

Logic Gate Principles

Logic gates are the fundamental building blocks of every digital circuit inside a computer. A logic gate is a small electronic circuit that takes one or more binary inputs, each either 0 or 1, and produces a single binary output according to a fixed rule. By combining millions of these simple gates on a silicon chip, computers perform complex calculations and make decisions.

There are three basic logic gates: AND, OR and NOT. The AND gate produces 1 only when both inputs are 1. The OR gate produces 1 when at least one input is 1. The NOT gate takes a single input and reverses it, turning 0 into 1 and 1 into 0.

Each gate has one or more inputs and exactly one output.

Gate outputs depend only on the current inputs, not on past values.

Gates are combined in circuits to perform arithmetic, logic and control tasks inside the CPU.

Truth Tables for AND, OR and NOT

A truth table is a simple chart that shows every possible combination of inputs for a logic gate and the resulting output. Truth tables list all outcomes without leaving anything out, making them the most reliable way to understand how a gate behaves.

The AND gate truth table has four rows because each of the two inputs can be 0 or 1. The output is 1 only when both inputs are 1. The OR gate truth table also has four rows, with output 1 in three of them, because it activates when at least one input is 1. The NOT gate has just two rows, because it has one input that it simply flips.

AND truth table: output is 1 only when both inputs are 1.

OR truth table: output is 1 when at least one input is 1.

NOT truth table: output is the opposite of the single input.

Combined Gate Circuits: NAND, NOR and XOR

When basic gates are connected together, they form new gates with different behaviour. A NAND gate is an AND gate followed by a NOT gate. It produces 0 only when both inputs are 1. A NOR gate is an OR gate followed by a NOT gate. It produces 1 only when both inputs are 0.

An XOR gate, short for Exclusive OR, produces 1 when the inputs are different and 0 when they are the same. XOR gates are used in arithmetic circuits inside the CPU for binary addition. A half adder uses one XOR gate and one AND gate to add two single-bit numbers.

NAND gate output is 0 only when both inputs are 1.

NOR gate output is 1 only when both inputs are 0.

XOR gate output is 1 when inputs are different, 0 when they are the same.

Practical Work

1. Draw the truth table for the AND gate.
2. Draw the truth table for the OR gate.
3. Draw the truth table for the NOT gate.
4. Trace the output of an AND gate fed into a NOT gate for every pair of inputs.

Scenario-Based Questions

1. A school door has a lock that opens only when two conditions are both true, the teacher inserts the key and the teacher enters the correct PIN. Name the logic gate that represents this rule and write its truth table.
2. A traffic light system turns on the pedestrian signal if button A is pressed OR button B is pressed. Name the gate, write its truth table, and explain why only one button needs to be pressed.
3. A security camera sends a 1 signal when there is NO movement in the restricted zone, so it can focus on that area. Name the gate being used and explain what happens to the output when the input changes from 0 to 1.
4. A teacher sets a rule: a pupil scores 1 if the homework is submitted on time AND the work is neat. Two pupils, Tunde and Emeka, submit on time but Tunde's work is neat while Emeka's is not. Predict the output for each pupil and name the gate.
5. An alarm rings when the door sensor reads 1 OR the window sensor reads 1 OR the fire sensor reads 1. Name the type of gate needed and explain why at least one input must be 1 for the alarm to ring.
6. A lab computer starts only when the power switch is ON and the network cable is plugged in and the login is correct. Draw a simple diagram showing three AND gates feeding into a final output.
7. A pupil says a NOT gate has two inputs. Correct this and explain what a NOT gate actually does, giving one example from everyday life.

Learning Objectives

• Define an algorithm and state its characteristics.
• Describe the standard flowchart symbols.
• Draw flowcharts for sequence and for a decision.
• Turn an everyday task into ordered steps and a diagram.

Starter Scenario

A pupil wants to make a cup of hot tea. If the steps are jumbled, such as pouring the water before boiling it, the result is wrong. Clear, ordered steps are needed to succeed. A clear set of ordered steps to complete a task is called an algorithm, and computers depend on it completely.

What is an Algorithm

An algorithm is a step by step set of instructions for solving a problem or completing a task. Each step is simple and clear, and the steps are followed in a precise order. In cooking, a recipe is an algorithm because it lists exact ingredients and steps in order. In travel, a route description is an algorithm. In a computer, a program is an algorithm written in a language the computer understands. The key idea is that an algorithm is a plan, and the same plan can be written down in words, in pictures, or in a programming language.

Everyday examples of algorithms include the steps to brush your teeth, which are wet the brush, add paste, brush, rinse and spit. The steps to buy airtime are open the app, enter the amount, confirm and type the code. The steps to line up for assembly are stand in class order, walk out, stand in line and wait. In each one the order matters, because doing a step out of place changes the result.

Characteristics of a Good Algorithm

A good algorithm should be clear, so every step is easy to understand. It should be unambiguous, so each step has only one meaning. It should be finite, so it ends after a certain number of steps. It should be precise, so the input and output are well defined. It should be effective, so every step can actually be carried out. It should be ordered, so steps run from start to finish in a correct sequence. A good algorithm should produce the same correct result every time when followed carefully.

What is a Flowchart

A flowchart is a diagram that shows the steps of an algorithm using standard symbols joined by arrows. It lets you see the whole process at a glance and makes errors easy to spot. Using standard shapes matters because a rectangle always means the same thing to any reader, just as road signs share one meaning for all drivers. To read a flowchart, start at the first oval, move along the arrows, carry out each process you pass, check each decision, and follow the correct branch until you reach the end oval. The arrows are essential because they tell the reader which step comes next.

Drawing Simple Flowcharts

A sequence flowchart shows steps that always happen one after another with no choices. To draw one, write the start oval, then each action in a rectangle, then the end oval, all joined by arrows. For example, making a fruit drink follows the sequence Start, take a cup, pour the juice, add sugar, stir, and End. Each step is one rectangle in a straight chain. When drawing, keep one step in each shape, write short clear words, and always draw an arrow from one shape to the next.

When a flow can go two ways, add a diamond for the decision. The question inside must be answerable with yes or no, and two arrows leave the diamond, one for yes and one for no, each leading to the right next step. For example, going to school follows the sequence Start, check whether it is raining, if yes carry an umbrella then leave, if no leave directly, reach school and End. The diamond sends the flow down one of two branches. Clear labels on the two arrows, such as yes and no, stop the reader from guessing which path to take.

Any algorithm can be turned into a flowchart by changing each word step into its matching symbol. Simple actions become rectangles, questions become diamonds, and the order becomes arrows. Drawing the flowchart by hand first, using a ruler and pencil, is a reliable way to keep the shapes neat and the arrows straight.

Algorithmic Thinking

Algorithmic thinking is the habit of breaking a problem into small, clear steps and putting those steps in the right order. People use algorithmic thinking every day without knowing its name, when a cook follows a recipe, when a student lists the steps for getting to school, and when a trader counts change in a fixed way.

When a task is broken down like this, the set of ordered steps is called an algorithm. A good algorithm has four important characteristics. It is definite, so each step has one clear meaning. It is finite, so it has a definite end and does not run forever. It produces output, so the user gets a visible result at the end. And it is effective, so every step can actually be carried out.

Definite, every step has one clear meaning.

Finite, the steps come to an end after a certain number.

Output, the algorithm produces a result the user can see.

Effective, each step can really be carried out.

Algorithmic thinking is the thinking skill behind programming. In this week's periods learners will write algorithms, draw them as flowcharts, and prepare for writing real programmes in Week 10.

Flowchart Symbols and Their Meanings

A flowchart is drawn with standard shapes, and every shape has one fixed meaning, so any reader understands the picture. The main symbols are the oval, the rectangle, the diamond, the arrow and the parallelogram.

The oval, also called the terminal, marks the start and the end of the flowchart. Every flowchart begins with a start oval and finishes with a stop oval. The rectangle, called the process box, shows an action or step such as add the sugar or print the receipt. The diamond, called the decision box, asks a question that can be answered yes or no, such as Is it raining? The arrow, called the flow line, connects the shapes and shows the direction in which the steps move. The parallelogram, called the input or output box, shows data entering or leaving the computer, such as type the number or display the answer.

Oval, start and end of the flowchart.

Rectangle, an action or process step.

Diamond, a yes or no decision.

Arrow, the direction of flow between steps.

Parallelogram, input or output of data.

Learners should match every part of an algorithm to its correct symbol, so that a word step becomes the right shape on the diagram.

Reading a Flowchart

To read a flowchart, begin at the first oval and follow the arrows from shape to shape. At a rectangle, carry out the action it describes. At a diamond, answer the question and follow the branch that matches, yes or no. The reading ends at the stop oval.

Reading skills help learners check their own diagrams and spot mistakes. If an arrow points the wrong way, or a decision has no yes or no label, the flowchart will send the reader the wrong way, just as an incorrect recipe step ruins the meal.

Start at the first oval and follow the arrows.

Do what each rectangle says, one step after another.

At a diamond, answer the question and follow the correct branch.

Finish when the stop oval is reached.

Constructing Flowcharts for Everyday Tasks

Constructing a flowchart follows a simple method. First write the steps of the task in order as plain sentences. Then decide which shape each step needs. Finally draw the shapes with a ruler and pencil, link them with arrows, and check by reading the finished picture from start to end.

For example, consider the task of getting ready for school. The main steps can be listed as start, wake up, brush teeth, dress, check whether breakfast is ready, and go to school. The decision Is breakfast ready? is a diamond with two branches. If yes, eat breakfast and then go to school. If no, go to school directly.

Using a ruler and pencil keeps the shapes neat. Each shape should hold one short step, and every arrow should point clearly to the next shape. A flowchart with one step per shape is far easier to read and to turn into code later.

Flowcharts for Simple Computations

Flowcharts are also used for simple computations, tasks where the computer takes a number, works on it and shows an answer. A common example is finding the area of a rectangle.

The flowchart reads as follows. Start. Read the length L and the width W of the rectangle, shown in parallelograms. Process the calculation, Area equals L times W, shown in a rectangle. Finally display the area, shown in a parallelogram, and stop. This pattern, input, process, output, is the shape of nearly every simple computation.

Read the two input values in parallelograms.

Calculate in a process rectangle, such as Area equals L times W.

Display the result and stop.

Learners can repeat this pattern for other computations, such as finding the total cost of items or converting miles to kilometres, which strengthens the link between flowcharts and real programmes.

Practical Work

1. Write the steps for making a fruit drink as an ordered algorithm.
2. Draw a flowchart with a decision for whether to carry an umbrella.
3. Match each flowchart symbol with its meaning.
4. Write the algorithm for buying airtime in four clear steps.

Scenario-Based Questions

1. A pupil wants to make a cup of tea but writes the steps in this order: drink the tea, boil water, put tea bag in cup, pour boiling water. Explain why this algorithm fails and rewrite the steps in the correct order.
2. A school wants a flowchart that asks a pupil for their class. If the class is JSS 3, the flowchart prints Welcome to JSS 3. For any other class, it prints Sorry, this system is for JSS 3 only. Identify which flowchart symbol you would use for each step and draw the flowchart.
3. A farmer wants an algorithm to decide whether to irrigate his crops. The rule is: if the soil moisture is below 30 percent, irrigate; otherwise, do not irrigate. Write the algorithm and say which flowchart symbol represents the decision.
4. A teacher says an algorithm must have a start and an end. Explain why an algorithm without a clear end point can cause problems and give an example of an everyday task with a definite end.
5. A pupil draws a flowchart but uses rectangles for decisions and diamonds for processes. Identify the mistake, explain the correct use of each symbol, and say why using the wrong symbol confuses the reader.
6. A library needs an algorithm to check if a borrower can take a book. The rules are: if the borrower has fewer than 3 books and the book is not reserved, the borrower can take it. Otherwise, the borrower cannot. Write the algorithm in steps and identify the decisions.
7. A beginner programmes a robot to move forward, turn left and pick up an object. Write a simple algorithm with exactly five steps and suggest what flowchart symbols would be used for each step.

Learning Objectives

• Explain what programming is and the parts of a program.
• Describe the input, process and output model.
• Write a simple program plan in pseudocode.
• Find and fix a simple error in a program.

Starter Scenario

A chief gives a driver, a chef and a market trader the same set of instructions, but each one is written in their own style. The driver needs a route, the chef needs a recipe and the trader needs a price list. Similarly, people and computers need instructions in a form they understand. Programming is writing instructions in a form a computer can follow, and the form is called a programming language.

What is Programming

Programming is the process of writing instructions for a computer to carry out. The instructions, taken together, are called a program. A program is different from an algorithm. An algorithm is a plan that anyone can understand, while a program is the same plan written in a programming language so that a computer can run it. People who write programs are called programmers, and nearly every app, game, website and device you use is built on programs.

A programming language has a fixed set of rules and words that a computer understands. Humans write in the language, and the computer translates it into the 0s and 1s it uses. Some languages use visual blocks that snap together, such as Scratch, while others use typed words, such as Python. Both describe the same ideas, just in different forms. Scratch is a good first language because you build programs from blocks, and Python is a typed language that reads almost like simple English.

The Input, Process, Output Model

Almost every program follows three parts. Input is the data that goes into the program. Process is the work the program does on that data. Output is the result the program gives back. In a calculator, the two numbers are the input, the multiplication is the process, and the displayed answer is the output. In a greeting program, the user's name is the input, joining the name to a greeting is the process, and showing the full greeting is the output.

Everyday devices follow the same model. In an ATM, the card and PIN are the input, checking the details is the process, and dispensing money or showing a message is the output. In a GPS, the current position is the input, finding the route is the process, and showing the map and directions is the output. In a music app, your search is the input, finding the song is the process, and playing the chosen song is the output. Thinking of any task in these three parts makes writing a program much clearer.

The input, process, output model maps straight onto a flowchart from Week 9. The parallelogram for input and output becomes the input and output steps, and the rectangle for process becomes the processing action. So when a learner writes a program, they first choose what data comes in, what processing happens, and what result should come out, exactly as they did with flowcharts.

Writing and Debugging a Simple Program

A simple greeting program follows the input, process, output model. It asks for a name, joins the greeting to it, and shows the result. In Scratch, you could use a block that asks the name, another that joins the words, and a block that says the result. In Python, the same idea is written as a few typed lines of code. Reading these steps aloud shows the exact order the program follows.

A program runs from top to bottom, one instruction at a time, just like a flowchart follows arrows. To predict what a program does, follow each line in order and jot down the values as you go. For a greeting that uses a name, the input of the name must come before the output uses it, otherwise the program has nothing to display. Changing the order changes the effect.

A bug is an error that stops a program from running correctly. Debugging is the process of finding that error and fixing it. Common bugs include typing a word wrongly, connecting blocks in the wrong order, using the wrong symbol, or forgetting a required part such as closing a quote. A reliable way to debug is to read the program line by line, run it to see the error message, and then compare each part with the intended steps. Fixing a bug is not failing, it is part of normal programming, and every programmer, even the most experienced, debug programs all the time.

A short program meant to greet a user instead shows nothing because it tries to display a greeting before the name has been given. The fix is to move the input step before the output step. Learners should identify the ordering error and describe the correct order, which mirrors the debugging skill used at the start of this period.

Programming Basics and Language Levels

Programming is giving a computer a clear set of instructions to follow. A program is a complete set of instructions that tells a computer how to perform a specific task. A simple program might ask for a number and then double it, while a complex program like a web browser handles millions of instructions every second.

Programming languages are grouped into levels. Machine language uses only 0s and 1s and is the only language a computer understands directly, but it is very hard for humans to read. Assembly language uses short codes such as ADD or MOV, which is easier but still tied to one type of processor. High-level languages such as Python, Scratch and Java use words close to everyday English. They must be translated into machine language before the computer can run them, but a compiler or interpreter does this automatically.

Simple Program Structures and Pseudocode

Even complex programs are built from a few simple structures. Sequence runs instructions one after another in order. Selection makes a choice, such as if the score is above 50, then say pass, otherwise say try again. Repetition repeats a group of instructions until some condition is met. Together these three structures build every app and game.

Pseudocode is a planning tool that looks like a mixture of English and program words. For example, the pseudocode for a greeting program might read ask for a name, then welcome the name, then show the message. Because pseudocode is not tied to one language, the same plan can be turned into Scratch, Python or any other language.

Programming Environments and Careers

Programs are written using an integrated development environment, often called an IDE, which gives programmers a place to type code, check for errors and run their program in one window. When a high-level program is ready, the computer translates it into machine language. Compilers translate the whole program at once into a runnable file, while interpreters translate and run the program line by line.

Programming skills open up many careers. Software developers build apps, games and office programs. Web developers create websites, and data analysts write programs that turn information into reports and charts. In Nigeria, banks, telecom companies such as MTN and Glo, and government agencies all employ programmers to build systems that serve millions of customers every day.

Practical Work

1. Write pseudocode for a program that greets a named user.
2. Describe the input, process and output of an ATM transaction.
3. Find the ordering error in a greeting program and correct it.
4. Write two differences between an algorithm and a program.

Scenario-Based Questions

1. A pupil writes a program that asks for two numbers and is supposed to add them, but it shows the product instead. Name this type of error and describe the step-by-step process the pupil should follow to find and fix it.
2. A school receptionist wants a program that asks for a visitor's name, asks whether the visitor is a parent or a staff member, and then prints a welcome message with the correct title. Write pseudocode for this program using sequence and selection.
3. A teacher says a program with an infinite loop will never stop. Give an example of an everyday task that could be written as an infinite loop and explain why it would be a problem on a computer.
4. A market trader wants a program that keeps asking for item prices until the trader types 0, then prints the total. Explain why iteration is needed here instead of just sequence, and write a short pseudocode.
5. A pupil says Scratch is a programming language but Python is not. Correct this statement by explaining what both Scratch and Python are and how they differ.
6. A student writes a program: ask for a number, if the number is greater than 10 print Big, otherwise print Small. Test the program mentally with the values 5, 10 and 15 and write the expected output for each.
7. An ATM machine follows the input-process-output model. Describe the input, the process and the output for one complete ATM transaction from insertion of the card to collection of cash.

Learning Objectives

• Describe the parts of an email message.
• Compose, attach, send and reply to email safely.
• State the uses of presentation software and the parts of its window.
• Choose a layout and arrange slides in a sensible order.

Parts of an Email Message

An email message has several fields. The To field holds the address of the recipient. The Cc field holds additional recipients who are copied, and the Bcc field holds recipients who are copied without being shown. The Subject field is a short summary of the message. The body holds the message itself. The attachment field holds files sent with the message.

The subject line is the most important part of a short message. It tells the recipient what the message is about before the body is opened, so it should be specific. A subject such as Assignment on Computer Parts is useful, while a subject such as Hello gives no information.

How Email Travels

When the message is sent, it goes first to the mail server of the sender, which is the computer that holds the account. The server looks up the address of the recipient and passes the message along the internet to the mail server that holds that account. The message then waits there until the recipient opens the mailbox and reads it.

Every email address has two parts separated by the at sign. The part before the at sign is the name of the account, and the part after it is the domain that holds the account. An address such as amina@cba.edu.ng means that the account named amina is held by the cba.edu.ng domain.

Delivery depends on both servers being online and connected. When a message cannot be delivered, a notification is returned to the sender. This is why a message that appears to have been sent should still be checked for a delivery notification.

Composing and Sending

Composing means writing a new message. Replying means answering a message that was received, and the reply keeps the original message above the new text. Forwarding means sending someone else's message on to a third person. A blind reply, in which the recipient cannot see who else received the message, is used for confidential replies.

Text in an email should be short. A message that needs several paragraphs is better sent as an attachment. Before sending, check three things: the addresses in the To field, the spelling of the subject, and that the right file is attached. A message sent to the wrong address cannot be recalled.

Attachments and Responsible Use

An attachment is a file sent with the message. Documents, pictures, sound and video can all be attached. A file that is compressed is sent as a single smaller file. Large attachments can be rejected by a mail server, so very large files are sent using a file sharing service instead.

Email is used for communication that should be recorded, such as a message to a teacher about a result. A subject line is required so that the message can be filed and found later. A professional email is polite, uses full sentences and does not use text abbreviations.

Care is needed with unknown senders. A message that asks for a password, an account number or money is almost always a scam. Personal details and passwords must never be sent in a message to an address that has not been confirmed as genuine.

Uses of Presentation Software

Presentation software produces slides for an audience. It is used for teaching a lesson, reporting project findings, advertising a product, explaining a proposal at a meeting and guiding a discussion. The slides are shown on a computer screen or a projector, one slide at a time.

Presentation software is closely related to word processing and spreadsheets. A chart made in a spreadsheet can be copied into a slide, and a report made in a word processor can be summarised into slides. Objects such as text, pictures, tables and charts can be moved, resized and formatted in the same way in all three programs.

Parts of the Presentation Window

The title bar shows the name of the file. The menu bar or ribbon holds the commands. The slide pane shows a small picture of every slide in the file, and clicking a picture selects that slide. The slide area is where the selected slide is edited. The notes pane holds the notes for the presenter. The status bar shows the number of slides.

The view buttons change how the file is displayed. Normal view is used for editing. Slide sorter view shows all the slides as pictures and is used for rearranging them. Slide show view fills the screen and is used when presenting. Notes view shows the notes page for printing.

Layouts and Placeholders

A layout is the arrangement of placeholders on a slide. The common layouts are title slide, title and content, title and two content, title only, section header, comparison and blank. Choosing the layout before typing places the title and the content boxes in the right positions.

A placeholder is a labelled box that holds the title or the main content. Text typed into a placeholder takes the formatting of the master, which keeps the presentation consistent. Content placeholders can also hold pictures, tables and charts, so the layout should match the type of content.

Sequencing Slides

Slides must be arranged so that the argument makes sense. The usual order is a title slide, then an introduction, then the main points in order, then a summary and a question slide. Slide sorter view is the quickest way to check and change the order.

A presentation on a topic taught over several lessons needs more than one slide per lesson point. Each slide should carry one idea. If a slide holds five unrelated points, the audience has to hold all of them in mind at once and loses the thread.

Practical Work

1. Compose a short professional email and attach a file to it.
2. Create a presentation with a title slide, a section header and a content slide.
3. Switch to slide sorter view and move a slide to a new position.
4. Run the first three slides in slide show view to a classmate.

Scenario-Based Questions

1. A pupil sends a message about an assignment to the wrong address. Explain why it cannot be recalled.
2. Explain the difference between Cc and Bcc and give a reason for using each.
3. Your friend receives a message asking for a bank password. Explain what to do and why.
4. A presentation has ten slides and the conclusion appears as slide 3. Explain the problem and the fix.
5. Explain why the slide sorter view is checked before a presentation is delivered.

Learning Objectives

• Revise every topic of the First Term.
• Practise questions on networks, number systems and programming.
• Identify and settle weak areas before the examination.
• Plan the final week of revision.

Review of Networks and the Internet

A network is two or more devices connected so they can share resources. Networks are named by the area they cover: a PAN around one person, a LAN in one building, a MAN across a city and a WAN across a country or the world. The internet is the largest WAN.

The key devices are the network interface card, the hub, the switch, the router, the modem, the access point and the firewall. Data moves in packets, and the protocols TCP/IP, HTTP, HTTPS and DNS decide how those packets are addressed, moved and secured.

Digital safety is part of the topic. Passwords are kept private, unknown links are not clicked, and https is used for any page that takes personal data.

Review of Number Systems and Data Representation

A number system is built on a base. The decimal system is base 10, the binary system is base 2, the octal system is base 8 and the hexadecimal system is base 16. The value of a digit depends on its place value.

To change a binary number to decimal, add the place values above each 1. To change a decimal number to binary, divide by 2 and read the remainders from bottom to top. To change binary to hexadecimal, group the bits in fours and replace each group.

All data is stored in binary. Text is stored through codes such as ASCII and Unicode, images through the colour numbers of each pixel, and sound through samples taken many times a second. The units of data grow from the bit to the byte, the kilobyte, the megabyte, the gigabyte and the terabyte.

Review of Logic, Algorithms and Programming

A logic gate takes one or more bits and gives one bit. The AND gate needs both inputs to be 1, the OR gate needs at least one, and the NOT gate flips its single input. Every gate can be shown in a truth table.

An algorithm is a step by step plan. It is clear, finite and effective. A flowchart shows an algorithm with the oval, the rectangle, the parallelogram and the diamond joined by arrows.

A program is an algorithm written in a language a computer can run. Most programs follow the input, process and output model. An error in a program is a bug, and finding and fixing it is called debugging.

Answering Examination Questions

Objective questions reward accuracy, so read every option before choosing. Short answer questions reward precision, so give exactly what is asked. In a difference question write both parts in the order asked. In a list question number each item so that it can be marked.

In a calculation, show the working even when the answer is correct, because method earns marks. In a diagram, label every part clearly.

Plan the last week of revision. Spend more time on the topics that were weakest in the class test, and end with a light review the evening before the paper.

Practical Work

1. Write the four network types and one example of each from memory.
2. Convert 1101 to decimal and 13 to binary without looking at your notes.
3. Draw the truth tables for AND, OR and NOT from memory.
4. Write the algorithm for a simple everyday task in five steps.

Scenario-Based Questions

1. Explain how you would revise nine weeks of work in four evenings.
2. Explain why reading notes once is a weak method of revision and give a better method.
3. A learner mixes up a switch and a router. Explain the difference between the two.
4. A learner says binary 10 equals decimal 10. Correct the learner.
5. Describe how a program plan differs from the finished program.

Examination and Continuous Assessment Practice

These questions are taken from the First Term examination and Continuous Assessment papers for this class. Answer them in full sentences.

1. Three classmates each hold a document on a phone and want every one of them to have all three documents. Define a computer network, state the devices on a network are called, give the reasons networks are set up, and explain how a school network meets the classmates' need.
2. (a) Define Digital Citizenship and state three (3) qualities of a good digital citizen. (b) Explain the term Digital Footprint and how students can maintain a positive online reputation. (c) Mention two (2) dangers of unsafe online behaviors (e.g., cyberbullying or sharing personal data).
3. A pupil connects a Bluetooth headset to a phone, a school laboratory has 30 computers sharing one printer, a university links campuses in different parts of Abuja, and the whole world is linked together. Classify each of these four situations as a PAN, LAN, MAN or WAN, and give the meaning of each term.
4. A learner says the internet and the World Wide Web are the same thing, and another says Wi-Fi is the internet. Define each of the three terms, explain the difference between the internet and the web, and correct the two statements.
5. A school wants a reliable, high-speed connection that many computers can use, and it must pay for the service. Explain what the internet is, name the services it carries, define an Internet Service Provider, and explain how a school chooses and pays for its connection.
6. A community centre wants internet, and a pupil at home already has wireless access. Name the means of accessing the internet, and explain the difference between Wi-Fi and the internet.
7. A learner searches for information and finds thousands of results, some of them advertisements. State how a learner should search safely, and the questions a learner should ask in order to judge a web page before trusting it.
8. A learner sends a photograph from a phone to a printer in another building, and the network must deliver it. State the steps data follows as it travels across a network, define the terms sender, receiver, medium and node, and compare a client-server network with a peer-to-peer network.

Learning Objectives

• Answer every section of the examination paper.
• Complete the practical task accurately within the time allowed.
• Apply internet safety and presentation conventions.
• Analyse the result and plan the Second Term revision.

Before the Examination

Arrive early and confirm that the practical computers are working. Lay out two pens, a pencil, an eraser, a ruler and the identification card. Read the instruction sheet and note the required file name, folder and format before starting.

During the Written Paper

The paper will include objective questions that test single facts and classifications. It will also include short answer questions that test definitions, differences and short explanations.

Answer every question, beginning with the ones you are sure of. In a difference question, write both parts. In a list question, number the items so that each can be marked.

During the Practical Paper

Work in the order given by the task. Create the file, add the content, apply the required design, add the required effect, then save. Save at each stage so that a power failure does not remove all the work.

Check the finished file against the task: the right number of slides, the right layouts, a picture that is not stretched, a title on every slide, the required transition and the exact file name in the correct folder.

After the Examination

The marked script is analysed by counting the marks lost on each question. A question that most learners missed identifies a topic to reteught in the Second Term.

The Second Term begins with revision of the weak topics and then moves to new work. The Second Term plan includes databases, more advanced networking and further practice with software.

Practical Work

1. Read the whole instruction sheet before touching the keyboard.
2. Note the required file name, folder, slide count and effect before starting.
3. Save the practical file at each stage rather than only at the end.
4. Run the presentation from the first slide to the last before the time ends.
5. Check the finished file against every item in the task before the time ends.
6. Note the topics that felt weakest for the Second Term revision plan.

Scenario-Based Questions

1. Explain why most marks in a practical examination are lost on the instruction rather than on the skill.
2. Describe how you would check a finished five slide presentation against the task.
3. Explain how the result of the examination is used to build the Second Term plan.
4. A candidate has eight minutes left and the file has not been saved. Explain the priority order.
5. Explain why the exact file name matters in a practical examination.
6. Explain the difference between an objective question and a short answer question.
7. A candidate has completed the content of a presentation but not the animation. Explain what marks this still earns and why.
8. ODELAMI

First Term Examination Practice Questions

These questions are taken from the First Term examination and Continuous Assessment papers for this class. Answer them in full sentences.

1. (a) Define Digital Citizenship and state three (3) qualities of a good digital citizen. (b) Explain the term Digital Footprint and how students can maintain a positive online reputation. (c) Mention two (2) dangers of unsafe online behaviors (e.g., cyberbullying or sharing personal data).
2. (a) Differentiate between a Web Browser and a Search Engine, giving two (2) examples of each. (b) Explain what a URL is and state its main function when browsing the internet. (c) Outline three (3) tips for conducting effective and safe searches on the internet.
3. (a) Define a Computer Network and list three (3) classifications based on geographical coverage (e.g., LAN, MAN, WAN). (b) State two (2) reasons why networking computers is important in modern offices and schools. (c) Mention two (2) network devices used in setting up a computer network.
4. (a) What is Cybersecurity? State two (2) common security threats or malware types. (b) Explain why strong passwords and firewalls are important for computer systems. (c) Define Software Piracy and state why it is considered an illegal practice.