How to Revise for Maths Exams at KS3 and GCSE

Maths revision means doing, not reading. Reading your notes or watching worked examples feels productive but changes very little. The cycle that actually builds skill is: attempt a problem yourself, check your answer, understand exactly where you went wrong, then retry a similar question without looking at the solution. That loop — attempt, check, understand, retry — is what maths revision looks like.

Why maths revision is different from essay subjects

In English or history, revision often means learning content: quotations, dates, key arguments. In maths, the content is a smaller part of the problem. You may know that the formula for the area of a circle is πr², but still lose marks on an exam question because you squared the diameter rather than the radius, or forgot to round to the required number of significant figures.

The DfE's mathematics programmes of study identify fluency, mathematical reasoning, and problem solving as the three core aims of maths education from KS3 onwards. Fluency — the ability to recall and apply procedures accurately — only develops through repeated, active practice. You cannot revise your way to fluency by reading.

This is why the most common maths revision mistake is passive re-reading: going over class notes, highlighting textbook examples, watching YouTube solutions. All of that feels like revision, but none of it tells you whether you can actually do the procedure independently.

Step 1 — Identify your weak topics first

Before doing any practice questions, spend fifteen to twenty minutes mapping where your marks are most at risk. There are two good ways to do this.

Topic checklist method: Most GCSE maths specifications (AQA, Edexcel, OCR) publish a full topic list on their websites. Print or copy the list and rate each topic honestly: confident, needs work, or very weak. Focus your revision time on the middle and weak categories first — not on topics you already understand well.

Past-paper analysis method: Do one past paper under timed conditions, mark it, and list every question you dropped marks on. Group them by topic. If you lost marks on three separate questions that all involved ratio and proportion, that topic rises to the top of your revision list.

The Education Endowment Foundation's guidance on maths at KS2 and KS3 highlights the importance of identifying and addressing gaps in foundational knowledge before moving on to more complex material. For GCSE students, algebraic manipulation, proportional reasoning, and graph interpretation are common areas where foundations are shakier than they appear.

Step 2 — Use active practice, not passive re-reading

Once you know your weak topics, the revision routine for each topic follows the same pattern:

Study one worked example closely — understand each step, write out why it works.

Close the example and attempt a similar question from scratch, without looking.

Check your answer against the mark scheme or worked solution.

If wrong, diagnose — did you use the wrong method, make an arithmetic error, or misread the question?

Retry a different question from the same topic.

This method is sometimes called the worked-example effect and is well-supported by cognitive science: studying an expert's solution and then attempting independent practice is more effective than either reading alone or practice without any model.

BBC Bitesize provides free worked examples and practice questions for GCSE maths across all major topics, with step-by-step solutions that are useful for the study-then-attempt cycle.

Step 3 — Work through past papers under timed conditions

Past papers are the most important revision tool in the final weeks before a maths exam, particularly at GCSE. They do three things that topic-by-topic practice cannot: they force you to switch between topics (as the real exam does), they apply time pressure, and they show you exactly how questions are worded in the actual exam.

Where to find past papers: GCSE past papers are freely available on the exam board websites. For the three main UK boards:

AQA: aqa.org.uk — navigate to your qualification and subject

Edexcel (Pearson): qualifications.pearson.com

OCR: ocr.org.uk

All three boards publish both question papers and mark schemes, which are essential for self-marking. Ofqual regulates all GCSE qualifications in England, and its register lists every accredited qualification with links to the awarding body.

How to use them: Set a timer for the full exam duration. Sit at a desk with only the equipment allowed in the real exam (calculator or no calculator, depending on the paper). Do not pause, look things up, or check answers mid-paper. Mark the completed paper using the official mark scheme.

GCSE maths has two or three papers depending on the board: at least one non-calculator paper and at least one calculator paper. Practise both types separately — the skills needed for non-calculator arithmetic are different and need deliberate attention.

Worked example: spotting and correcting an algebra error

The following example shows a common Year 10/GCSE algebra mistake and how to identify what went wrong.

| Student's working | Correct working
Question | Solve 3(x + 4) = 21 | Solve 3(x + 4) = 21
Step 1 | 3x + 4 = 21 | 3x + 12 = 21
Step 2 | 3x = 17 | 3x = 9
Step 3 | x = 5.67 | x = 3
Error type | Forgot to multiply 4 by 3 when expanding the bracket | —
What to revise | Expanding single brackets — practice 10 similar examples | —

The error here is not carelessness: it is a gap in understanding of how the distributive law works. Diagnosing the error type (not just "I got it wrong") is what allows targeted revision.

Step 4 — Review mistakes systematically with an error log

After every past paper or practice session, record your mistakes in a simple error log rather than just looking at the mark scheme and moving on. An error log takes five minutes to fill in and transforms how you use your revision time.

A basic error log has four columns:

Topic | Question summary | My mistake | What I need to revise
Ratio and proportion | Share £240 in ratio 3:5 | Added parts instead of dividing | Ratio method — 10 more practice questions
Quadratics | Factorise x² + 5x + 6 | Got signs wrong in brackets | Factorising with positive and negative coefficients
Probability | Combined probability tree | Did not multiply branches | Tree diagrams — redo from basics

Review the log once a week. Topics that appear repeatedly become your priority for the next week's practice sessions.

How long to revise and when to start

The EEF's evidence consistently supports spaced practice — shorter sessions spread across weeks — over concentrated cramming in the days before an exam. For maths specifically:

KS3 assessments: Start three to four weeks before. Two to three sessions of forty minutes per week is sufficient for most students.

GCSE maths: Start structured past-paper revision no later than six weeks before the first paper. In the final fortnight, aim for four to five sessions per week, alternating topic practice with full papers.

The minimum effective session length for maths is about thirty minutes — enough time to attempt three to five questions, mark them, and understand errors. Sessions longer than ninety minutes tend to produce diminishing returns; rest and sleep are when memory consolidation actually happens.

Frequently asked questions

How many past papers should I do for GCSE maths?

Most students who prepare well complete between five and ten full past papers before the GCSE maths exam. Start with one paper early in revision to diagnose weak topics, then use topic practice for several weeks, and return to full papers in the final four to six weeks. Doing ten papers without analysing your errors is less effective than doing five papers and keeping a careful error log after each one. The point of a past paper is not the score — it is the diagnostic information.

What is the best way to revise maths if you keep making the same mistakes?

Repeated mistakes usually mean one of three things: a misconception (wrong mental model of how a rule works), a procedural gap (you know what to do but skip or confuse a step), or a reading error (misinterpreting the question). To find out which, write out your working in full and compare it step-by-step against a correct solution. If the error is conceptual, return to a basic explanation of the rule before attempting further practice. If it is procedural, write out the steps as a checklist and follow it explicitly until the procedure is automatic.

Should I revise maths topics I already know, or focus on weak areas?

Focus the majority of your revision time — roughly 70% — on weak and developing topics. Spending most of your revision time on topics you already understand feels more comfortable but yields far fewer additional marks. That said, brief maintenance practice on confident topics (two or three questions every week or two) prevents the forgetting curve from eroding skills you have already secured. The topic checklist or first past paper is the best guide to how to allocate your time.

How do I revise maths without a calculator for the non-calculator paper?

Non-calculator revision requires explicit practice without one — it sounds obvious, but many students reach into their pocket or phone by habit. For the non-calculator paper, practise: mental arithmetic with decimals and fractions, long multiplication and division by hand, simplifying fractions without a calculator, and estimating answers to check for plausibility. BBC Bitesize has a dedicated non-calculator section with practice questions. Aim for at least two or three non-calculator practice sessions per week in the month before the exam, entirely device-free.

For personalised maths tutoring that works through problems step by step without handing over answers, visit aitutors.me.