GCSE Computer Science
Numeracy is heavy and specific: learners convert between denary, binary and hexadecimal, add in binary, work with base 2 storage units, calculate image, sound and compressed file sizes and routing costs, and reason with truth tables and DIV and MOD. Literacy centres on close reading of the Unit 2 scenario and requirements, precise technical vocabulary, short and extended judgement answers in Unit 1, and code annotation and test commentaries. The single biggest thing Key Stage 3 should build is fluent place value in base 2 and base 16, so that storage and file size calculations become routine.
- First taught
- September 2025
- Amount of literacy work
- Medium
- Amount of numeracy work
- High
- Specification
- Open the WJEC specification (PDF)
How this GCSE is assessed
- Unit 1: Understanding Computer Science: Digital examination 1 hour 30 minutes, 50%, 80 marks
- Unit 2: Computer Programming: On-screen examination based on a pre-released brief, 2 hours, 50%, 80 marks, set and marked by WJEC
Skills that use Planning and organising for different purposes, audiences and context
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Extended answers on legal, ethical, social and environmental impact
Unit 1 includes short and extended answers, and the legal, social, ethical, environmental and professional dimensions run through every topic. AO3 asks learners to make reasoned judgements, for example on e-waste, privacy or AI.
Literacy: Planning and organising for different purposes, audiences and context, Connectives and syntax
Getting pupils ready
- Year 7
- Pupils write one paragraph on whether old mobile phones should be recycled rather than thrown away, using the connectives because, however and therefore.
- Year 8
- Pupils write two linked paragraphs giving one advantage and one disadvantage of facial recognition cameras in shops, each backed by an example.
- Year 9
- Pupils plan and write a 300 word balanced answer on whether AI chatbots should be allowed for homework, ending with a reasoned judgement.
Show the specification wording and the LNF statements
Where it is in the specification: Unit 1, Overview of unit, page 9; Section 3.1, page 28
“consider the broad legal, social, ethical, environmental and professional consequences relevant to the use of technology”
Progression step 3
I can adapt my writing style and structure to suit the audience, purpose and context, e.g. suitable balance between facts and viewpoints, a precise conclusion.
I can use paragraphs and make links between them.
I can use an increasing range of connectives to organise my ideas in sentences, paragraphs and whole texts.
Progression step 4
I can use summary, discussion of issues, detailed explanations and logic when covering a topic.
I can organise and construct my writing effectively, connecting and developing my ideas for a range of different contexts.
I can use a range of connectives specifically when organising my ideas in whole texts for different purposes.
Progression step 5
I can write extended pieces which include detailed evidence and information for different purposes and audiences within and across different disciplines.
I can convey objectivity and impartiality on complex topics, using a range of linguistic devices.
I can organise writing in an appropriate form, ensuring content is detailed within and between paragraphs or sections, developing and sustaining ideas coherently.
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Annotating code, writing test commentaries and refining
Learners annotate code so a competent third party can follow it, present test outcomes with commentaries, and explain and evaluate the changes they make when refining a solution. Test plans must use typical, extreme and erroneous data.
Literacy: Proofreading, editing and improving, Planning and organising for different purposes, audiences and context, Vocabulary, spelling, grammar
Getting pupils ready
- Year 7
- Pupils add comments to their Scratch or Python game explaining what each part does, then swap with a partner who checks the comments make sense without running the code.
- Year 8
- Pupils complete a test table for a number-guessing program using typical, extreme and wrong inputs and write one sentence explaining each result.
- Year 9
- Pupils fix a bug in a given Python program and write a short commentary saying what went wrong, what they changed and how they retested it.
Show the specification wording and the LNF statements
Where it is in the specification: Unit 2, Sections 2.3.1 and 2.4.1, pages 25 to 26
“present test outcomes with detailed and informed commentaries”
Progression step 3
I can reflect on, edit and redraft to improve the quality of my expression, and use a range of strategies to ensure greater clarity.
I can explore different ways to plan, draft and present my work appropriately.
I can present my work appropriately in digital contexts.
Progression step 4
I can improve writing through independent review and redrafting.
I can select and use appropriate strategies to plan and develop my writing for different purposes and audiences.
I can present my work appropriately in digital contexts using appropriate digital conventions, e.g. thumbnails, language preferences.
Progression step 5
I can improve the content, structure and accuracy of my writing through critical reflection, review and editing, responding constructively to feedback.
I can summarise confidently, adapting style and form for the reader or intended audience and purpose for writing.
I can understand and use formal conventions of language in a range of purposes, making effective use of reference tools and accuracy aids.
Good to know
- No marks are set aside for spelling, punctuation and grammar. The assessment objectives on page 28 cover only knowledge (AO1), application (AO2) and analysis (AO3), so accuracy of language is not separately credited.
- Both units are answered on screen, page 5: Unit 1 is a "Digital examination: 1 hour 30 minutes" and Unit 2 is an "On-screen examination based on a pre-released brief: 2 hours". Pupils need to type extended answers and calculations.
- The specification does not say whether a calculator is allowed in either unit, so centres should check the WJEC instructions for each series. Pupils should be able to do binary, hexadecimal and storage calculations by hand.
- No notes are allowed into the Unit 2 examination, page 28: "learners are not permitted to take any prompts or notes into the examination." A clean copy of the pre-release is provided.
- Unit 1 mixes question types, page 5: "Questions requiring objective responses, short and extended answers."
- Storage units use 1,024, not 1,000, page 13: "kilobyte (i.e. 1,024 bytes)". Pupils who learn 1,000 in Science or Mathematics need the difference made explicit.
- Appendix B, pages 34 to 36, fixes the operators and pseudocode conventions used in questions: "Logical operators AND OR NOT XOR will be in upper case." DIV and MOD are defined with worked examples such as "11 MOD 2 = 1".
- Appendix A, page 32, marks the numeracy strands for geometry and measurement and for statistics and probability as N/A for both units, so there is no graphing or statistics demand.
Links with other GCSEs
Place value, powers, ratio and percentage reduction are taught in Mathematics, so agreeing shared language (for example 'column value' and 'simplest form') with the Mathematics department in Years 7 to 9 will help pupils transfer these skills to binary and file size work.
Source: WJEC GCSE Computer Science specification, teaching from 2025, for award from 2027, Version 3, September 2025.