Past paper questions, worked and runnable

GCSE Computer Science past paper questions worked through step by step: trace tables, programs to write, algorithms to fix. Every answer is a program you can run in your browser, with the lesson that teaches it.

141 worked answersfree, runs in your browser

The programming paper is where most marks are won and lost, and reading a mark scheme does not show you how to get there. So each page here takes one real question, works through it the way you would in the exam, shows where marks are usually lost, and gives you the answer as a program to run and change.

How to use these

1. Open the paper on the exam board's site and try the question on paper first, against the clock.
2. Check your answer against the worked one, step by step.
3. Run the program. Change the numbers and predict what happens before you press Run.
4. If a step made no sense, do the lesson linked at the bottom of the page.

These are our own explanations of published exam questions. They are not written or endorsed by any exam board. Question papers and mark schemes remain the copyright of the boards and are linked, not copied.