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Cambridge IGCSE Computer Science

Cambridge IGCSE Computer Science Paper 1 practice questions

Paper 1 is worth 50% of Cambridge IGCSE Computer Science. The questions below are original practice questions with worked answers, so you can test yourself the way the real exam will — and see exactly what an examiner is looking for.

What is on Paper 1?

  • Paper 1 covers computer systems.
  • It is a written paper of 1 hour 45 minutes, worth 75 marks — 50% of the IGCSE.
  • Questions are a mix of multiple choice, short answer and longer extended responses.
  • Always check the latest specification on your exam board's website, as details can change between exam years.

Paper 1 practice questions with answers

8 original questions across the 4 Paper 1 topics. Try each one before reading the answer.

  1. Cambridge: Data representation

    1. What is binary 1011 0000 in denary?

    • • 160
    • • 172
    • • 176
    • • 184

    Answer: 176

    128 + 32 + 16 = 176.

  2. Cambridge: Data representation

    2. How many bits does one hexadecimal digit represent?

    • • 2
    • • 3
    • • 4
    • • 8

    Answer: 4

    Hex digits map exactly onto four-bit nibbles.

  3. Cambridge: Data transmission

    3. Which part of a packet holds the destination address?

    • • Payload
    • • Header
    • • Trailer
    • • Checksum only

    Answer: Header

    Headers carry addressing and sequence information.

  4. Cambridge: Data transmission

    4. Explain why packets may arrive out of order.

    Answer: Each packet may take a different route depending on network congestion

    Packet numbers allow correct reassembly.

  5. Cambridge: Hardware, CPU and logic

    5. Which register holds the address of the next instruction?

    • • MDR
    • • ACC
    • • PC
    • • CIR

    Answer: PC

    The program counter tracks execution position.

  6. Cambridge: Hardware, CPU and logic

    6. State the three stages of the machine cycle.

    Answer: Fetch, decode, execute

    Repeated continuously while the computer runs.

  7. Cambridge: Software, the internet and security

    7. Which is system software?

    • • Spreadsheet
    • • Operating system
    • • Photo editor
    • • Web game

    Answer: Operating system

    System software manages the computer itself.

  8. Cambridge: Software, the internet and security

    8. Give two tasks performed by an operating system.

    Answer: Memory management and file management (also peripherals, security, user interface)

    Any two management roles are creditable.

Where Paper 1 marks are usually lost

  • Giving vague definitions — examiners want the precise technical term.
  • Losing marks in trace tables by skipping rows or misreading loop conditions.
  • Writing code or pseudocode that ignores the exact input and output the question asks for.
  • Answering 'explain' questions with a single fact instead of a fact plus a reason.
  • Mixing up binary, denary and hexadecimal conversions under time pressure.

How to pick up the extended-answer marks

  • Underline the command word and the focus of the question before writing — most dropped marks come from answering a different question.
  • Plan for one or two minutes: three or four points, each backed by evidence and explained.
  • Keep linking back to the question in every paragraph, not just the conclusion.
  • For 'evaluate' or 'how far do you agree' questions, weigh both sides and finish with a clear judgement.

Timing that works under pressure

  • Check the marks per question and give each one time in proportion, keeping spare minutes for checking at the end.
  • Bank the short questions first, then return to the longer answers with your remaining time.
  • If a question stalls for more than two minutes, write down what you know and move on — partial marks still count.
  • Leave five minutes to check spelling of key terms, units and whether any question part was skipped over a page break.

Practise the whole paper in the app

These Paper 1 topics have 264 questions in total, plus flashcards, cram mode and Grade 9 Push challenges.

Open GCSE Computer Science Cram mode

Revise each Paper 1 topic

Cambridge IGCSE Computer Science Paper 1 FAQs

What topics are on Cambridge IGCSE Computer Science Paper 1?
Paper 1 assesses data representation, data transmission, hardware, software, the internet and cyber security.
How long is Cambridge IGCSE Computer Science Paper 1?
It is a 1 hour 45 minutes written exam worth 75 marks, which is 50% of the IGCSE. Check your board's latest specification for any changes.
How should I revise for Computer Science Paper 1?
Practise answering questions rather than rereading notes. Short daily sets of five questions per topic, marked straight away, expose weak areas faster than a long passive revision session.

ReviseRush is an independent educational revision aid. It is not affiliated with, endorsed by or connected to AQA, Edexcel, OCR, WJEC, Pearson or any exam board. All notes and questions are original. Always check content against your official course and specification. No grade outcome is guaranteed.