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CIE · IGCSE · Computer Science

Free CIE IGCSE Computer Science
Practice Paper

8 mixed-difficulty practice questions in the style of real CIE IGCSE papers — answers, mark-scheme-style explanations, and the official exam structure all on one page.

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What the real CIE IGCSE Computer Science paper looks like

Paper 1 (Multiple Choice)
40 multiple-choice questions, 1 mark each. 45 minutes. Tests breadth of knowledge.
Paper 2 (Core) / Paper 4 (Extended)
Structured written paper. 1 hour 30 minutes (Core) or 1 hour 45 minutes (Extended). Tests depth of understanding and application.
Paper 6 (Alternative to Practical)
Written paper assessing practical skills for candidates without lab access. 1 hour. Worth ~20% of the total.
Total exam time: ~3 hours, depending on tier (Core vs Extended).
Grading: Grades: A* (highest) to G (lowest), with U (ungraded). Most universities require C or above.

Mini practice paper: 8 questions

Mixed-difficulty questions from across the Computer Science syllabus. Tap "Show answer" after each to check yourself.

Q1 · Difficulty 1/3

Which unit is used to describe the smallest addressable unit of data storage in a computer?

  1. Bit
  2. Word
  3. Nibble
  4. Byte
Show answer & explanation
✓ Answer: A — Bit
A bit (binary digit) is the smallest unit of data, holding a value of either 0 or 1. A nibble is 4 bits; a byte is 8 bits; a word is a processor-dependent grouping of bytes, all of which are larger than a single bit.
Q2 · Difficulty 1/3

Which of the following best describes a procedure in programming?

  1. A variable that stores the result of a calculation
  2. A loop that repeats a block of code a fixed number of times
  3. A named block of code that performs a task but does not return a value
  4. A named block of code that performs a task and returns a value
Show answer & explanation
✓ Answer: C — A named block of code that performs a task but does not return a value
A procedure is a named block of code that carries out a specific task but does not return a value to the calling code. Option A describes a function, not a procedure. Option C describes a variable. Option D describes a count-controlled loop.
Q3 · Difficulty 1/3

A string variable word is assigned the value "Cambridge". Which of the following correctly returns the length of this string?

  1. LENGTH(word) returns 8
  2. LENGTH(word) returns 10
  3. LENGTH(word) returns 9
  4. LENGTH(word) returns 7
Show answer & explanation
✓ Answer: C — LENGTH(word) returns 9
The string "Cambridge" contains exactly 9 characters (C-a-m-b-r-i-d-g-e), so LENGTH(word) returns 9. Option A (8) is a common off-by-one error where students miscount. Option B (10) incorrectly adds an extra character, perhaps imagining a null terminator. Option D (7) results from miscounting and skipping multiple characters.
Q4 · Difficulty 1/3

Which of the following best describes the purpose of cache memory in a CPU?

  1. To hold the address of the next instruction to be fetched
  2. To permanently store the operating system kernel
  3. To store frequently used data and instructions for rapid access
  4. To increase the total amount of RAM available to programs
Show answer & explanation
✓ Answer: C — To store frequently used data and instructions for rapid access
Cache memory stores frequently or recently accessed data and instructions so the CPU can retrieve them much faster than fetching from RAM, reducing the average memory access time. Cache is volatile and not used for permanent storage of the OS. Cache does not extend RAM capacity. The Program Counter holds the address of the next instruction.
Q5 · Difficulty 1/3

Which of the following best describes 'open-source software'?

  1. Software that can only be used on computers connected to the internet
  2. Software whose source code is freely available for anyone to view, modify, and distribute
  3. Software that is free to download but cannot be modified by the user
  4. Software owned by a company that charges a licence fee for its use
Show answer & explanation
✓ Answer: B — Software whose source code is freely available for anyone to view, modify, and distribute
Open-source software is defined by the availability of its source code, which anyone can inspect, modify, and redistribute. Option A describes freeware, not open-source software. Option B describes proprietary software. Option C is unrelated to the open-source definition.
Q6 · Difficulty 1/3

What is the output of the following pseudocode sequence? x ← 5 y ← 2 x ← x + y OUTPUT x

  1. 5
  2. 2
  3. 7
  4. 10
Show answer & explanation
✓ Answer: C — 7
Sequence executes line by line: x is assigned 5, y is assigned 2, then x is reassigned to x + y = 5 + 2 = 7. The output is therefore 7. Students who answer 5 ignore the reassignment of x. Students who answer 10 may incorrectly multiply. Students who answer 2 read only the value of y.
Q7 · Difficulty 1/3

Which pseudocode construct is used to repeat a block of statements a fixed, known number of times?

  1. IF ... THEN ... ENDIF
  2. REPEAT ... UNTIL
  3. FOR ... TO ... NEXT
  4. WHILE ... DO ... ENDWHILE
Show answer & explanation
✓ Answer: C — FOR ... TO ... NEXT
A FOR...TO...NEXT loop is a count-controlled iteration used when the number of repetitions is known in advance. WHILE and REPEAT...UNTIL are condition-controlled loops used when the number of repetitions is not known. IF...THEN...ENDIF is a selection construct, not iteration.
Q8 · Difficulty 1/3

A data block is transmitted and the checksum calculated at the receiver is different from the checksum sent with the data. What does this indicate?

  1. An error has occurred during transmission of the data
  2. The data was compressed during transmission
  3. The receiver is using a different character set to the sender
  4. The parity bit was set to the wrong value before sending
Show answer & explanation
✓ Answer: A — An error has occurred during transmission of the data
A mismatch between the received checksum and the recalculated checksum indicates that one or more bits in the data block have been altered during transmission, signalling an error. Option A is incorrect because compression is unrelated to checksum mismatch. Option B confuses parity checking with checksum verification. Option D describes a data interpretation issue, not a transmission error detected by checksums.
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CIE IGCSE Computer Science FAQ

What does the CIE IGCSE Computer Science exam look like?
The CIE IGCSE Computer Science exam is structured across 3 components. Paper 1 (Multiple Choice): 40 multiple-choice questions, 1 mark each. 45 minutes. Tests breadth of knowledge. Paper 2 (Core) / Paper 4 (Extended): Structured written paper. 1 hour 30 minutes (Core) or 1 hour 45 minutes (Extended). Tests depth of understanding and application. Paper 6 (Alternative to Practical): Written paper assessing practical skills for candidates without lab access. 1 hour. Worth ~20% of the total. Total exam time: ~3 hours, depending on tier (Core vs Extended).
Can I download a free CIE IGCSE Computer Science past paper?
Real CIE past papers are published directly by CIE on their official website. Kramizo doesn't redistribute copyrighted past papers, but we do generate free AI-written practice papers in the exact same style — same command words, same difficulty tier, same mark conventions. Use this practice paper as warm-up, then time yourself on official past papers before exam day.
How is CIE IGCSE Computer Science graded?
Grades: A* (highest) to G (lowest), with U (ungraded). Most universities require C or above. Kramizo's practice questions are tagged with difficulty 1-3 mapping roughly to the lower, middle, and top grade boundaries you'll encounter in the real exam.