Why We Built This Report
Every year, Cambridge publishes examiner reports after each exam series. These documents are gold: hundreds of observations from the people who marked your paper, describing exactly what students got wrong and why marks were lost. The problem is that these reports are buried in PDF downloads most students never find — and each one covers only a single exam session. Nobody had read them all together, looked for patterns across years, and translated them into actionable revision advice. So we did. The State of GCSE & IGCSE Maths 2025 is built from 515 distinct examiner observations drawn from 7 CIE 0580 examiner reports spanning 2018 to 2024. We also catalogued 53 mark scheme patterns — the specific rules that govern how marks are awarded and lost. Here is what we found.
Finding 1: Three Topics Account for 71% of All Flagged Mistakes
When you read every examiner report from 2018 to 2024, a clear hierarchy emerges. Geometry generated 130 flagged mistakes (25.2% of the total). Number generated 122 (23.7%). Algebra generated 114 (22.1%). Together, these three topics account for 71% of every mistake Cambridge examiners have flagged across seven years of sitting. The implication for your revision is stark: if you have limited time, fixing your weaknesses in these three areas will address the vast majority of the ways marks are lost on CIE 0580. Within geometry, the recurring failures are missing reasons in angle proofs, errors in bearing problems, and incorrect use of arc length and sector area formulae. Within number, the main culprits are rounding errors, incorrect significant figures, and confusion between standard form operations. Within algebra, sign errors — particularly in the quadratic formula — appear in almost every examiner report.
- Geometry (25% of flagged mistakes): missing geometric reasons, bearing errors, arc/sector formula misuse
- Number (24%): rounding, significant figures, standard form
- Algebra (22%): sign errors in quadratic formula, factorisation slips, index law mistakes
Finding 2: 'Show That' Questions Have the Highest Mark-Loss Rate Relative to Ability
This is the finding that surprised us most. 'Show that' and 'prove' questions appear across all difficulty levels, but our mark scheme pattern analysis reveals that they have a disproportionately high mark-loss rate even among high-ability students. The reason is counterintuitive: students who can do the maths lose marks because they do not show enough working. In a normal 'find' question, you need to show the method and arrive at the right answer. In a 'show that' question, the answer is already given to you in the question stem. The marks are awarded entirely for the quality and completeness of your intermediate working. Examiners are instructed to look for jumps — places where a step is missing. Each missing step costs a method mark. The golden rule: if in doubt, write it out. An extra line of working never loses marks, but a missing line almost always does.
Finding 3: The Same Mistakes Have Been Flagged Every Year Since 2018
The most striking pattern in the data is not the mistakes themselves — it is the consistency. The same 10 to 15 mistakes appear in every examiner report across the entire seven-year dataset. This is not because the exam is getting harder; it is because student preparation has not adapted. Sign errors in the quadratic formula. Missing geometric reasons. Incorrect frequency density. Reverse percentage confusion. Index law mistakes. These are not difficult concepts. They are patterns that students repeatedly fail to recognise as exam traps, even though the traps appear every single year. If you are preparing for a Cambridge maths exam, the most efficient revision strategy is not to study new material — it is to systematically eliminate the mistakes that every cohort before you made on the same question types.
Finding 4: Follow-Through Marking Can Save More Marks Than Students Realise
One of the 53 mark scheme patterns we catalogued — and one of the most underexploited by students — is follow-through marking. If you make an error in part (a) of a question and carry that wrong value into part (b), the examiner marks the mathematics in part (b), not the number. If your method in part (b) is correct given your (wrong) answer from part (a), you still earn the method marks. This means that abandoning a multi-part question after one error is one of the most expensive habits in the exam. You should attempt every part of every question, even if you know an earlier answer was wrong. Write the method, carry through your value, show the working. You may earn more marks than you think.
Download the Full Report
These four findings are a summary of what is in the full report. The complete 20-page document includes grade boundary trends across five exam boards from 2018 to 2025, a full topic frequency heatmap showing which subtopics appear most often across seven years of papers, the complete ranked list of the top ten common mistakes with specific fixes, a section on mark scheme patterns including how M marks, A marks, and B marks work in practice, a board-by-board comparison of paper structure and grade thresholds, and topic predictions for June 2026. The report is free. Download it at the link below, or take our free diagnostic quiz first to find out which of these findings apply most to your own exam preparation.