JAMB UTME - Computer Studies - 2025

Bayanin Amsa

Networks sit on a scale from smallest to largest coverage area: LAN (one building), then the next size up, MAN (a whole city), and WAN (a country or the globe). Between a single-building LAN and a city-wide MAN sits a network that can stretch across several buildings on one site, such as a university or company campus, while still being confined to a fairly small area.

This is the Campus Area Network (CAN). It is larger than a LAN because it links multiple buildings, but it is still limited in size, typically covering less than about 30 square miles, which is far smaller than the city-wide reach of a MAN or the national and global reach of a WAN.

Exam takeaway: the key distinguishing detail in this question is the phrase several buildings combined with a size limit well under a full city, which points specifically to a Campus Area Network rather than a LAN, MAN, or WAN.

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The system development life cycle describes the recognised stages a new computer system passes through, from identifying a need to putting the finished system into use. The commonly taught stages include analysis, design, development or coding, test running, and implementation.

• Design: creating the plan and structure for how the new system will work, based on the requirements gathered earlier.
• Test running: checking the developed system for errors and confirming it works correctly before it is put into full use.
• Implementation: putting the completed and tested system into actual operation, including installing it and training users.

"Observation" is not one of the formally named stages of the system development life cycle. While observing how a system performs can happen informally during testing or after implementation, it is not itself a distinct, named stage in the standard model; it is instead an activity that can occur within stages like analysis or evaluation, rather than a separate, defined phase.

Exam reminder: memorise the standard named stages of the system development life cycle (typically analysis, design, development, testing, and implementation) so that an unfamiliar or generic term like "observation" can be quickly identified as not belonging to the list.

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The central processing unit (CPU) is the part of the computer that carries out instructions, and it is built from a small number of cooperating components.

Two of those components are the arithmetic and logic unit (ALU), which performs calculations and logical comparisons, and the control unit, which directs and coordinates the entire process, it fetches instructions from memory, decodes what each instruction means, and generates the signals that tell the ALU and other parts of the computer exactly when and how to act. Together, the ALU and the control unit, along with registers, make up the CPU.

Input, memory, and simple binary values such as "1/0" are not units that combine with the ALU to form the CPU, memory is a separate component the CPU reads from and writes to, and input refers to devices, not an internal CPU component.

Exam tip: remember the CPU's two core functional units by their roles, the ALU calculates and compares, the control unit directs and sequences everything else.

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To add numbers written in different bases, each number must first be converted into a common base, usually base \(10\), before the addition is carried out.

Converting \(1011_2\) to base \(10\):\[1011_2 = (1 \times 2^3) + (0 \times 2^2) + (1 \times 2^1) + (1 \times 2^0) = 8 + 0 + 2 + 1 = 11_{10}\]Converting \(122_4\) to base \(10\):\[122_4 = (1 \times 4^2) + (2 \times 4^1) + (2 \times 4^0) = 16 + 8 + 2 = 26_{10}\]Adding the two base \(10\) values gives:\[11 + 26 = 37\]

A frequent error is adding the digits of the two numbers as if they were already in the same base without converting first; always convert every number to base \(10\) before combining values from different number systems.

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Programs written by humans in a high-level language (such as Python or Java) are not directly understood by a computer's processor, which can only execute instructions in machine code (binary). A special program called a language translator converts the human-written code into a simpler form the machine can run.

A compiler is one such translator. It takes the entire source program written in a high-level language and translates it, all at once, into machine code (or another lower-level form) that the computer can execute directly. Because it converts the whole program from a complex, human-readable language down into the simple binary instructions the hardware executes, it fits the description of translating a program into a simpler language the computer can run.

An interpreter also translates code but does so line by line as the program runs, rather than producing a complete translated program beforehand; while related, this distinguishes its mode of operation. A processor is the hardware component that executes instructions rather than a translation program itself, and an algorithm is simply a step-by-step procedure for solving a problem, not a translation tool at all.

Exam reminder: compilers and interpreters are both language translators, but a compiler translates the entire program in one pass before execution, which matches the description of converting a full program into a simpler executable form.

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The question describes a small program written so that it can travel from one computer to another over the internet and run inside another program, typically a web browser, once it arrives. This kind of small, portable program embedded in a web page is called an applet.

An applet is designed to be downloaded automatically along with a web page and executed within the browser, adding interactive features such as animations or calculations to what would otherwise be a static page. Mail refers to messages sent between users, not a program in itself; an algorithm is a step-by-step plan for solving a problem, not something that is transmitted and executed; and data packages are simply chunks of data moved across a network, not executable programs.

Exam takeaway: associate the idea of a program sent from one computer to another across the web to be run there specifically with an applet, since it is defined by being both a program and something that travels and executes remotely inside a browser.

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Logic gates produce an output based on fixed rules applied to their inputs. An AND gate only outputs HIGH when every input is HIGH, a NOT gate simply inverts a single input, and a NOR gate outputs HIGH only when all of its inputs are LOW, the opposite behaviour of what is being described.

The gate that produces a HIGH output whenever at least one of its inputs is HIGH is the OR gate. Its truth table shows that the only way to get a LOW output is for every single input to be LOW at the same time; as soon as one or more inputs become HIGH, the output switches to HIGH.

Remember the OR gate by the phrase "any one is enough": if any single input is HIGH, the output is HIGH.

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Software development begins with a problem statement, but that statement must first be broken down into a precise sequence of logical steps before any programming language is used.

The activity of translating a problem statement into an ordered series of steps describing exactly what the program must do is known as creating the algorithm. An algorithm is a step-by-step procedure for solving a problem, often expressed in plain language, pseudocode, or a flowchart, and it forms the logical blueprint that guides everything that comes afterward.

The other options describe later or unrelated stages. Coding is the subsequent step where the algorithm is translated into actual instructions in a specific programming language. Debugging happens after code has been written, when errors in that code are located and fixed. Writing documentation involves recording how the finished system works for future reference, which happens throughout or after development, not at the initial planning stage.

When a question describes converting a problem into "sequential steps" before any code is written, that description points to algorithm creation, since coding only begins once the algorithm already exists.

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Malicious software is grouped by how it behaves once it infects a computer. Self-replication, the ability of a piece of malware to make copies of itself and spread to other files or systems without further action from an attacker, is the key feature that separates some categories from others.

A worm copies itself across a network without needing to attach to another program, and a computer virus attaches itself to a legitimate file or program and copies itself whenever that file is run or shared, so both of these are defined specifically by their ability to replicate. A program that disguises itself as legitimate or useful software while secretly carrying out harmful actions behaves differently: once it is installed, it performs its damaging function directly, but it does not make copies of itself or spread on its own; a user must be tricked into installing it again elsewhere for it to appear on another machine.

Software that secretly monitors a user's activity and sends the collected information to a third party, without the user's consent, is designed purely for covert surveillance and data theft, not for spreading itself between systems, which is exactly why it does not replicate in the way a worm or virus does.

When a question asks about self-replication specifically, focus on the defining mechanism of each malware type rather than treating "harmful" as the deciding factor, since several harmful programs never copy themselves at all.

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Computer devices are classified as either input devices, which send data or instructions into the computer, or output devices, which present processed results back to the user.

A mouse allows the user to point, click, and select items on the screen, sending positional and click data into the computer, making it an input device. A keyboard lets the user type letters, numbers, and commands into the computer, and a joystick is used to send directional and control signals, typically for gaming or simulation, into the computer. All three of these send data from the user to the machine.

A monitor, on the other hand, is a screen that displays visual results the computer has already processed, such as text, images, or video. Since it presents information to the user rather than sending information into the computer, it is classified as an output device, not an input device.

Exam tip: ask "does this device send data into the computer, or show data that came out of it?" A monitor always shows results, so it belongs with output devices, not the input devices listed alongside it here.

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Word processing software provides keyboard shortcuts as quick alternatives to using the mouse for common commands. Each shortcut is a fixed combination of keys assigned to one specific action, and these combinations are consistent across most Microsoft Office applications.

The shortcut that reverses, or "undoes", the most recent action performed in Microsoft Word is Ctrl + Z. Pressing it repeatedly continues stepping backward through the history of recent edits, one action at a time.

Ctrl + A selects all the text in the document, Ctrl + X cuts the selected text, removing it and copying it to the clipboard, and Ctrl + U applies or removes underline formatting on selected text. None of these three reverse a previous action, so none of them can be the undo command.

It helps to remember Ctrl + Z alongside its opposite, Ctrl + Y, which redoes an action that was just undone.

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A word processor is application software designed for creating and handling text documents. Its core functions cover the whole life cycle of a document, from first creating it to producing a final copy.

Users can write new text into a document, go back and edit that text by inserting, deleting, or reformatting words and paragraphs, and then print the finished document onto paper. These are not separate, competing capabilities; they are all standard, everyday functions built into any word processor such as Microsoft Word.

Because writing, editing, and printing are all genuine and commonly used features of a word processor, the complete and accurate answer covers all three rather than singling out just one.

Exam takeaway: when a question lists several correct, non-conflicting capabilities of the same software and one choice claims all of these are true, check whether every listed capability genuinely holds before ruling it out.

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An Automated Teller Machine (ATM) is a self-service banking terminal designed to let customers carry out basic banking transactions without needing a bank teller present.

Its most common and defining use is allowing a customer to withdraw cash from their bank account using a bank card and a personal identification number. ATMs may also support related services such as balance enquiries or deposits, but cash withdrawal is the core, everyday function that gives the machine its purpose.

Record keeping and budget making are tasks typically handled by accounting or spreadsheet software, not by a cash machine, and watching movies has no connection to banking terminals at all.

Examination reminder: associate the ATM directly with cash-related banking transactions, especially withdrawing money, rather than with general record-keeping software functions.

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Computers are classified by size, processing power, and typical use. Microcomputers are the small, relatively low-cost, single-user machines such as desktop computers and laptops that are designed for everyday tasks like word processing, record keeping, and communication.

Mainframe computers and supercomputers are built for organisations that need to process enormous volumes of data or perform extremely intensive calculations, such as national banks, large research institutions, or government agencies; they are expensive, physically large, and far beyond what everyday business tasks require. Minicomputers sit between these categories and were historically used by medium-sized organisations for tasks larger than a single desktop machine could handle, but they are still more than a small business needs for routine daily operations. A small business handling ordinary tasks such as invoicing, correspondence, and simple record keeping is best served by microcomputers, which are affordable, easy to maintain, and sized for a small number of users.

Examination reminder: match the scale of the computer to the scale of the task; "everyday tasks" and "small business" point to microcomputers, while "massive data processing" points to mainframes or supercomputers.

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Every programming or command language has strict rules that determine how its words, symbols, and punctuation must be arranged for a statement to be understood by the computer. If these rules are broken, the computer cannot interpret the instruction at all, even if the intended meaning would be obvious to a human reader.

This set of structural rules is called syntax. It defines things such as the correct order of keywords, how statements must be terminated, and how brackets or quotation marks must be paired. A program that violates syntax rules will produce a syntax error and will not run.

Algorithm refers to the logical sequence of steps used to solve a problem, which is a separate concept from how those steps are written down in code. Logic refers to the reasoning behind a solution, and a password is a security credential; neither of these describes the structural grammar of a language.

Examination reminder: keep syntax (structural rules of the language) distinct from an algorithm (the logical steps of a solution), since exam questions often test the two ideas against each other.

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Some keyboard combinations are reserved by the operating system to perform special control actions rather than typing characters. One of the most widely known of these on Windows-based systems is the combination that opens the Security or Task Manager screen, from which a user can choose to restart the computer, and on many older or unresponsive systems pressing it triggers a direct reboot.

Pressing Delete together with only one modifier key, or Ctrl and Alt without Delete, does not trigger this system-level interrupt. It is specifically the three-key combination of Ctrl, Alt, and Delete together that the operating system recognises as the reboot or system-interrupt command, because it was deliberately chosen as a combination unlikely to be pressed by accident during normal typing.

Remember this shortcut as a three-key combination; leaving out any one of the three keys changes its effect completely.

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In the BASIC programming language, certain keywords instruct the interpreter on how to treat a line of code, and some lines are meant purely for human readers rather than for execution.

The keyword REM (short for "remark") marks the line that follows it as a comment. When the BASIC interpreter encounters REM at the start of a line, it ignores everything on that line during program execution. Programmers use REM statements to leave explanatory notes inside their code, describing what a section of the program does, without affecting how the program runs.

This distinguishes REM from other statement types. An executable statement is one the interpreter actually carries out, such as an assignment or a PRINT command, and REM is deliberately excluded from execution. It is also not correct to call it simply "un-executable statement", since that phrase does not capture its actual purpose, which is documentation, not merely being skipped. It is not an output statement either, since it produces no visible result on screen.

Whenever a question mentions REM in BASIC, associate it directly with the term comment, since its sole function is to hold explanatory text that the computer ignores.

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Different application programs are built around one core purpose, even though they may offer several secondary features. Identifying that core purpose is the key to this question.

Microsoft Word is a word-processing program, and its central purpose is to let the user type, format, edit, and produce text-based documents such as letters, reports, and essays. Features like spell-check, formatting tools, and templates all exist to support this single main function: creating documents.

Word does not develop other applications, since it is not a programming or software-development tool. It is also not primarily a storage tool, even though it can save files, because saving is a supporting feature rather than its defining purpose. Browsing the internet is the job of a web browser, a completely different category of application.

Examination reminder: when identifying the purpose of well-known software, focus on its primary, defining function rather than any secondary feature it happens to include.

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System software is the category of programs that manage a computer's own hardware and provide the platform on which all other programs run. The clearest example of system software is the operating system.

iOS, Ubuntu, and Chrome OS are all operating systems: they control the computer's or mobile device's hardware, manage memory and storage, and provide the interface through which a user can then install and run application software such as word processors or games. Because their job is to manage the underlying machine rather than to perform a specific user task, they are classified as system software.

They are not computer applications, since applications are installed on top of an operating system to perform specific tasks, not the other way around. "Computer utilities" and "application package" describe narrower categories, such as small maintenance tools or bundled sets of applications, neither of which matches what a full operating system does.

Examination reminder: whenever you see the name of an operating system in a question, classify it as system software, since its role is to manage the device itself rather than to perform an end-user task.

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Access methods describe how a computer locates and retrieves a specific record of data from storage, and their efficiency depends on whether every record must be checked along the way.

Sequential access requires the storage device to read through records one after another, in order, starting from the beginning, until the required record is reached. To retrieve a record located near the end of the file, every preceding record must first be read and passed over, which makes this method comparatively slow, especially for large files or when the required record is far from the start. Magnetic tape is a classic example of a storage medium that only supports sequential access.

The other access methods are all designed to reach a specific record more directly. Direct access (also called random access) allows the storage device to move straight to the physical location of the required record without reading through the ones before it. Indexed access uses a separate index that maps each record to its location, allowing the system to look up the index first and then jump directly to the record, combining fast lookup with organised storage. Random access is effectively the same principle as direct access, retrieving any record directly regardless of its position.

When a question asks which method is "least efficient" for retrieval, look for the one that must pass through preceding records in order, since sequential access is the only one listed that cannot jump directly to the required data.

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Before this machine was built, early computers had to be manually rewired or reconfigured with switches every time a different task needed to be run, which made changing a program a slow physical process. This computer introduced a design in which the instructions of a program, along with its data, could be stored electronically in the computer's own memory alongside each other, so the machine could read and execute instructions automatically without being physically rewired. This design idea is known as the stored-program concept, and it became the foundation for how virtually all modern computers operate.

The other concepts listed belong to computer networking rather than to the internal design of a single early computer. Packet routing and packet switching both describe how data is broken into small units and directed across a network to reach its destination, technologies developed decades later for communication between separate computers. Circuit switching describes an older telecommunications method, used in traditional telephone networks, where a dedicated connection is held open for the entire duration of a call. None of these three ideas describe how a single computer stores and executes its own instructions internally, which is exactly what this machine was built to demonstrate.

When a question links a historic computer to a "concept," check whether the concept concerns how the machine processes instructions internally (such as the stored-program idea) or how separate machines communicate over a network (routing, switching); these are two entirely different areas of computing history.

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Application packages are pre-written programs designed to help users perform specific tasks such as writing documents, managing spreadsheets, organising databases, or creating graphics. Different packages serve different purposes, and their popularity reflects how often ordinary users need that particular task.

Word processing, the creation and formatting of text documents such as letters, reports, and essays, is one of the most common computing tasks performed by students, office workers, and businesses alike. This everyday need makes the word processing package the one most widely used among general computer users.

By comparison, a database package is mainly used for structured record-keeping, a spreadsheet package is mainly used for numerical calculations, and a graphic design package is mainly used for illustration and image editing. These serve narrower, more specialised audiences than everyday text creation.

Exam takeaway: when comparing application packages by how widely they are used, favour the one tied to the most universal, everyday task, which for most computer users is producing text documents.

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A peer-to-peer network is a small network in which every connected computer, called a peer, has equal status. There is no dedicated server controlling the network and no strict hierarchy, so each peer can share files or resources directly with any other peer.

Because there is no central server managing user accounts, permissions, or access control, a peer-to-peer network generally has weaker security than a server-based network. Any computer that joins can potentially access shared resources on the other peers, and there is no single point where security policies are centrally enforced. Describing this arrangement as having a strong security system misrepresents how peer-to-peer networks actually work.

When comparing network types, remember that centralised control, including strong security enforcement, is a feature of client-server networks, while peer-to-peer networks trade that central control for simplicity and equal status among computers.

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Logic gates are the basic building blocks of digital circuits, and each type of gate follows a fixed rule for turning input signals into an output signal. A NOT gate is the simplest of these: it has only one input and one output.

A NOT gate performs logical inversion, meaning its output is always the opposite of its input. Since the input signal given is \(1\), the output must be \(0\). This can be summarised in a small truth table:

The output cannot be "either 0 and 1" at once, because a NOT gate produces exactly one definite output for a given input, never both simultaneously. Since a valid, single-value answer exists, "none of the above" is also incorrect.

Remember the NOT gate with a single rule: it always flips the input, 0 becomes 1, and 1 becomes 0.

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Every hardware component connected to a computer, such as a printer, graphics card, or mouse, communicates using its own particular signals and commands. The operating system cannot understand these signals directly, so it needs a piece of system software, called a device driver, written specifically for that hardware device.

A device driver translates the general instructions the operating system sends into the exact commands the specific hardware understands, and it translates the responses from the hardware back into a form the operating system can use. This is what allows the operating system to detect, configure, and control a wide range of different hardware devices without needing to know the internal engineering details of each one. Running application programs is the role of the operating system working together with application software, not the specific role of a device driver, and device drivers do not provide internet security; that function belongs to security software such as firewalls or antivirus programs.

Examination reminder: whenever a question ties a piece of software to controlling or enabling a specific piece of hardware, the expected answer is a device driver.

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Storage devices in a computer differ in whether they need continuous power to hold data. This difference matters because it determines what happens to stored information when the computer is switched off.

Non-volatile storage retains its data even after power is removed, which is why files saved on a hard disk, solid-state drive, or flash drive are still available the next time the computer is turned on. Volatile storage, such as RAM, behaves the opposite way, losing its contents the moment power is cut.

Sequential storage and direct storage describe how data is accessed, one item after another versus jumping straight to a location, not whether the data survives a power cut. Those terms answer a different question from the one being asked here.

Exam takeaway: link surviving a power loss directly to non-volatile storage, and keep access-method terms like sequential and direct separate from this power-related distinction.

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The storage position of a file isn't one of its numerous characters because, it can be stored either in a primary or secondary memory.

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When information travels across a network, it can pass through many intermediate points where it might be intercepted by someone other than the intended recipient. Protecting the confidentiality of that information during transit is a core concern in computer security.

Encryption addresses this by scrambling a message into an unreadable form using a mathematical algorithm and a key, so that only someone holding the correct decryption key can turn it back into readable content. This ensures the message can travel safely to its destination without being understood by a third party who intercepts it along the way.

Encryption does not filter unwanted spam messages, confirm who originally sent a message, or interpret the meaning of data; those are separate functions handled by spam filters, digital signatures, and application software respectively. Encryption's specific job is protecting the content of a message from unauthorised access during its journey.

Exam takeaway: tie encryption specifically to confidentiality during transmission, not to identifying senders or filtering unwanted content, which are different security functions.

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Computers can be classified by the type of processing technology they combine, based on whether they handle continuous or discrete data.

A hybrid computer is built to combine the features of both analog and digital computers in one system. It accepts and processes continuously varying physical measurements the way an analog computer does, converts these into digital form, and then processes them with the speed and precision of a digital computer. Hybrid computers are commonly used in situations that need continuous real-world measurement combined with digital accuracy, such as monitoring equipment in hospital intensive care units.

The other options describe single-technology or informal categories. A digital computer processes only discrete binary data, and an analog computer processes only continuous physical quantities; neither combines both approaches by definition. "Multipurpose computer" is not a standard classification term describing this combination of analog and digital functions in computer studies.

When a question describes a computer that "combines" analog and digital functions, that specific combination is the defining feature of a hybrid computer.

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Word processors, spreadsheets, database programs, graphics tools, and presentation software all share one feature: each is designed to let a user perform a specific, everyday task such as writing documents, calculating figures, storing records, drawing, or building slides. Software written to carry out these end-user tasks is grouped together as application packages.

Utility packages instead perform maintenance tasks such as compression, backup, or disk cleanup rather than direct user tasks. Operating system software manages the computer's hardware and resources and provides the platform on which application packages run; it is not itself a tool for writing, calculating, or presenting.

Exam takeaway: if a list of software items describes what an ordinary user directly works with to produce documents, numbers, images, or slides, it belongs to application packages, not utility or operating system software.

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The cursor is displayed on the monitor screen to help with navigation.
 

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Loops repeat a block of instructions, and sometimes a program needs to skip the remaining instructions for one particular pass through the loop without stopping the loop entirely. The continue statement does exactly this: when it is reached, the program immediately jumps back to the loop's condition check and begins the next iteration, skipping any code that comes after it within that pass.

For example, in a loop that processes numbers from 1 to 10 and needs to skip even numbers, a continue statement placed inside a condition that detects an even number would move straight to the next number without executing the remaining instructions for that particular value. This is different from a statement that would stop the loop altogether, since the continue statement only skips the current pass and allows the loop to carry on with the next one. "Skip statement," "jump statement," and "next statement" are not the recognised keywords used in mainstream programming languages for this behaviour.

Examination reminder: continue skips the rest of the current iteration and moves to the next one, while break would end the loop completely; these two are commonly confused in examinations.

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Every website is made up of multiple linked pages, but one page is designated as the main entry point that loads first when a visitor types the site's address or clicks its link. This main introductory page is called the home page.

The home page typically contains an overview of the website's content, navigation links to other sections, and introductory information that helps visitors find what they are looking for. From the home page, users can navigate to all the other pages that make up the rest of the site.

A bookmark is a saved shortcut to a specific web page stored within a browser, not the main page of a website itself. A search page is a page used to look up specific content, and a "task page" is not a standard web terminology term; neither describes the website's primary landing page.

Exam tip: always associate the term "home page" with the first, main page of a website that a visitor lands on by default.

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The standard computer keyboard used across most desktop and laptop systems is built around a fixed minimum key layout that includes the alphabet keys, number keys, function keys, punctuation keys, and control keys such as Shift, Ctrl, Alt, Enter, and the spacebar.

This standard layout is known as the 101-key keyboard, and it is the minimum arrangement recognised in computer studies. Some keyboards add extra keys, for example multimedia or Windows-specific keys, which increases the total beyond 101, but the base standard that every full-size keyboard is built on top of is 101 keys.

Exam takeaway: remember 101 as the baseline standard keyboard key count; extended keyboards add extra keys on top of this minimum for extra functions such as multimedia control or additional shortcuts.

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A network for distributing information is any system or arrangement that moves data, files, or resources from one point to another, whether between computers, through email servers, or by sharing a single output device.

Cloud storage distributes files across the internet to be accessed from multiple locations, several computers connected to one printer distribute print jobs to a shared device, and e-mail distributes messages between users across a network. All three genuinely move or share information between separate points.

Microsoft Word does not fit this description: it is a word-processing application used to create and edit documents on a single computer. It does not, by itself, move or share information between different computers or devices, which is why it is the one item that is not a network for distributing information.

When a question asks which item does not belong, check each item against the defining feature stated in the question, here, distribution of information between points, rather than just recognising the terms as computing-related.

Bayanin Amsa

Computer software is divided into system software, which manages the computer's own hardware and internal operations, and application software, which is written to help end users carry out specific, real-world information-processing tasks such as typing documents, managing accounts, or analysing data.

The description in the question, "a set of programs that direct computers to perform specific information processing activities for end users," points directly to this second category. Application software exists precisely because ordinary users need programs built for particular jobs: word processors for writing, spreadsheets for calculations, and database systems for record-keeping, all serving the end user's own tasks rather than the computer's internal housekeeping.

System software, by contrast, works mainly behind the scenes to keep the computer running rather than to serve a user's chosen task directly. The operating system is one specific type of system software responsible for managing hardware and resources, and translators (such as compilers and interpreters) convert program code into machine instructions; neither is defined by performing tasks chosen by an end user.

Exam tip: whenever a definition mentions serving "end users" and specific tasks rather than managing the machine itself, the term being tested is application software.

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Computer data is measured in units built from the bit, the smallest unit of digital information, which can be either 0 or 1. Larger units are formed by grouping bits together: a byte is made of \(8\) bits, and a nibble is defined as exactly half of a byte.

Since a byte contains \(8\) bits, half of that amount is\[\frac{8}{2} = 4\]bits. A nibble is therefore made up of \(4\) bits, which is enough to represent a single hexadecimal digit, one reason the nibble is a useful unit in computing.

Keep the size chain in mind: \(4\) bits make a nibble, \(8\) bits (two nibbles) make a byte, and multiples of bytes build up to kilobytes, megabytes, and beyond.

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Writing a program rarely produces perfectly working code on the first attempt. The process of locating faults, known as bugs, in the source code and fixing them so the program behaves as intended is called debugging.

Testing is related but distinct: testing is the act of running the program against various inputs to discover whether errors exist, while debugging is the follow-up work of tracing those errors back to their exact location in the code and correcting them. Editing simply means changing text in a file and coding means writing the original program instructions, neither of which specifically refers to locating and fixing faults.

Keep the terms separate: testing reveals that something is wrong, and debugging is the process of finding out why and putting it right.

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A computer network exists whenever two or more computers are linked together, whether by cables, fibre, or wireless signals, so that they can share resources such as printers, files, and internet access, or exchange data directly. The linking itself, the physical and logical connection between the machines, is what defines a network.

The other terms describe things that happen because of a network rather than the network itself. A connection is a general word for any link between two points and does not specifically describe computers joined for resource sharing. Communication is one possible outcome of a network (computers exchanging messages), but a network can exist purely for sharing a printer or storage device without any messaging taking place. Transfer describes moving data from one place to another, which is also just one activity that a network makes possible, not the structure that enables it.

When you see a question that names the act of linking machines together for shared use, the keyword to associate with it is always network, since networking is the umbrella concept and communication, transfer, and connection are all specific behaviours that a network supports.

Bayanin Amsa

Computers are classified by the type of data they process into analog, digital, and hybrid computers. This distinction depends on whether the values being measured or processed change in smooth, unbroken steps or in fixed, separate steps.

An analog computer works with physical quantities that vary continuously, such as temperature, pressure, voltage, or speed. These quantities do not jump from one fixed value to the next; instead, they flow smoothly through every possible value in a range, for example a thermometer's mercury column rising gradually rather than in sudden jumps. Because of this, analog computers are built to measure and process continuously varying data.

Digital computers, by contrast, process discrete data, meaning information broken into distinct, separate values, most commonly represented using binary digits (0s and 1s). "Discretely varying" and "intermittent" both describe data that changes in separate, interrupted steps rather than smoothly, which is the opposite of what analog computers handle.

Exam tip: link the word "analog" with anything that changes smoothly and without interruption, such as sound waves or temperature; link "digital" with anything counted in fixed, separate steps.