How to Revise IGCSE Maths After a Past Paper: A Five-Step Routine

1. Mark the paper and find where your working changed direction

Use the mark scheme that matches the exact paper, variant and examination series. Mark your original attempt before rewriting it, so you can still see what you did under the practice conditions.

Cambridge awards whole marks, not half marks. Follow the scheme's specific requirements for method and accuracy marks rather than inventing partial credit. If you cannot interpret a marking symbol or decide whether your alternative method earns a mark, flag the question for your teacher.

For each incorrect or incomplete answer, compare your working with a correct solution. Find the first step you could not justify. The final answer alone may hide whether you chose the wrong method, made a calculation slip, misunderstood the question or ran out of time.

Keep those categories practical. For example:

• Method gap: you did not know how to start a simultaneous equation question.
• Calculation slip: you used the right percentage method but multiplied incorrectly.
• Reading mistake: you found the area when the question asked for the perimeter.
• Time issue: you left a question unfinished and need to investigate whether the difficulty was the topic, the pace or both.

A question can involve more than one issue. The purpose is to choose useful practice, not to attach a perfect label.

2. Choose a specific skill to work on next

Write down the skill, the question reference and a short description of the error. Use a precise name such as “percentage decrease” or “expanding two brackets” rather than a broad heading such as “number” or “algebra”. You do not need to invent a syllabus topic code.

Choose a skill that appears in several mistakes or prevents you from completing other questions. You might start with one main topic and one small accuracy habit, such as keeping negative substitutions in brackets.

Review a lesson or worked example that explains the missing step. Then close the solution and explain the method in your own words. If you still cannot explain why the method works, take that exact question to your teacher instead of copying more examples without resolving the uncertainty.

Keep your original paper reference beside the correction. This makes it easier to return to the problem and compare your reasoning later.

3. Practise with a fresh example

Use new questions that require the same skill, rather than relying only on the answer you have just seen. Here is an original example of how to turn a percentage mistake into targeted practice.

Example: a price of £80 is reduced by 20%.

The reduction is 0.20 × 80 = £16. The new price is £80 − £16 = £64. Alternatively, 80% of the original price remains, so 0.80 × 80 = £64. Both methods agree.

If you had calculated 80 ÷ 20, write down why that was the wrong operation: 20% means 20 out of every 100, so the multiplier is 20 ÷ 100 = 0.20.

Try independently: a £60 item is reduced by 15%. What is its new price?

Answer: the reduction is 0.15 × 60 = £9, leaving £51. The equivalent calculation is 0.85 × 60 = £51.

Check your working as well as your answer. If the fresh question goes wrong, return to the first uncertain step and try another example after clarifying it. There is no fixed number of questions that proves a topic is mastered.

4. Return to the original question without the solution

After some time away from the worked solution, attempt the original question again on a clean page. Hide both the answer and your correction while you work.

Then try a different question with changed numbers or wording. Getting a remembered question right and applying the method to a new question provide different information; record which one you have done.

For an algebra example, check a proposed factorisation by expanding it:

(x + 2)(x + 3) = x² + 3x + 2x + 6 = x² + 5x + 6.

Matching the original expression checks the factorisation. If your middle term differs, revisit the pair of numbers you chose. Write the checking step in your correction so it is available the next time you practise.

5. Use the next paper to choose your next revision session

Attempt another paper when it fits your study plan and you have had time to address the issues you selected. There is no universal rule that everyone should complete a new paper every two or three days.

Check that the paper is suitable for your syllabus and examination year. Older papers can still contain useful practice questions, but their content, calculator rules or structure may differ. Follow the relevant paper instructions and your teacher's guidance.

Record the paper reference, practice conditions, score and skills that still need attention. Compare your working across papers: did you use the correct percentage base, include the required units, or show a step you previously omitted? Scores are useful context, but papers differ in content and difficulty.

Do not treat a percentage on one paper, or an average of unrelated papers, as a predicted final grade. Ask your teacher how the complete component combination and the relevant official grade thresholds apply.

Finish each review by writing one concrete next action, such as “practise percentage decreases, then check two fresh questions without the example”. For a place to begin, try a free IGCSE Maths lesson on StudyForA.