# 9709 Common Mistakes: What Cambridge Examiners Keep Reporting > Cambridge's 9709 examiner reports point to the same few mistakes on every paper: answers taken from a calculator without working, rounding too early, giving decimals when an exact answer is asked for, sloppy notation, and on Mechanics, missing force diagrams. None of these are about hard content, so they are the cheapest marks to win back. - Page: https://mathvsarham.com/articles/9709-common-mistakes-examiner-reports/ - Author: Arham (https://mathvsarham.com/about/) - Category: Cambridge A Level Maths (9709) - Part of: Cambridge A Level Maths 9709: Papers, Routes, Grading and How to Prepare (https://mathvsarham.com/articles/cambridge-a-level-maths-9709/) - Published: 2026-10-26 - Last checked: 2026-10-26 ## Key takeaways - No marks for unsupported calculator answers: show factorisation, substitution and each step. - Keep at least 4 significant figures in working, then give 3 significant figures; exact answers stay exact. - Paper 3: cubics and quartics must be factorised, not solved on a calculator. - Mechanics: draw an annotated force diagram, and use calculus when acceleration is not constant. - Statistics: rounding too early in normal distribution questions is one of the most reported errors. After every series, Cambridge publishes a Principal Examiner Report for 9709 that goes through each paper question by question. The June 2024 report is the source for everything below. What stands out is how little of it is about difficult content. Most lost marks come from how answers are written. ## 1. Why do calculator answers score zero? This is the biggest one, and it applies to every pure paper. The front of each question paper says "no marks will be given for unsupported answers from a calculator". * **Paper 11:** solving a quadratic needs factorisation, the quadratic formula or completing the square on the page. Quoting a formula without substituting values is not enough, and factors should expand back to the original quadratic. * **Paper 13:** examiners could not credit quadratic solutions, definite integrals, gradients, simultaneous equation solutions, intersection points or sums of series that appeared "from little or no working", even when they were correct. Equation solvers, programmable and graphical calculators are not allowed. * **Paper 33:** calculators are essentially for arithmetic, standard functions, and solving simultaneous linear and quadratic equations. Cubic and quartic equations must be factorised, or the marks for that part and anything depending on it can be lost. **Fix:** write the line that shows the method, even when you checked it on your calculator. ## 2. How many significant figures should you use? * Non-exact answers go to **3 significant figures** (1 decimal place for angles in degrees). To be sure the third figure is right, keep **at least 4 significant figures** throughout. The Mechanics and Statistics reports repeat this every time. * On **Paper 52**, many candidates rounded prematurely in normal approximation questions, which gave inaccurate table values. Examiners also flagged confusion over significant figures for decimals less than 1 (0.04567 to 3 s.f. is 0.0457). * When a question asks for an **exact** answer, a rounded decimal is not accepted, and exact answers should be simplified (no fractions divided by fractions), as **Paper 12** noted. * **Paper 42:** exact answers do not need to be turned into 3 significant figures at all. ## 3. Are you answering the question that was asked? * **Paper 31 and 32:** read the demand carefully. Finding the point where two lines intersect is not the same as *showing* that they intersect. * **Paper 32:** if you are asked to prove something, state the conclusion. Finding three side lengths does not show a triangle is isosceles until you say two of them are equal. * **Paper 12:** information in the stem of a question holds for every part, but information given in part (a) only holds for part (a). Watch for "it is given instead". * **Paper 21:** check the angle units before you start a trig question. ## 4. How much working does a "show that" question need? **Papers 22 and 23** both report that in "show that" questions every step must be visible, because the result is already printed. The syllabus defines "show (that)" as "provide structured evidence that leads to a given result". Going from line 2 to the given answer in one jump loses the final marks. ## 5. Which notation and terms do examiners expect? * **Paper 31:** leaving out brackets can turn a correct idea into an expression that scores nothing. * **Paper 12:** use the exact words for transformations: "translation" with a column vector, or "stretch" with the word "factor", its size and its direction. * **Paper 33:** know what is required when showing points on an Argand diagram. ## 6. What goes wrong in Mechanics (Paper 4)? * **Papers 41, 42 and 43:** a well-annotated force diagram helps you include every force in an equilibrium or F = ma equation. For collisions, draw before-and-after diagrams with directions to avoid sign errors in momentum equations. * **Paper 41:** when velocity is given as a function of time, you must use calculus. The constant acceleration (suvat) equations do not apply. * **Paper 43:** when a force is variable, using Newton's second law to find a constant acceleration earns no marks. ## 7. What goes wrong in Probability & Statistics (Paper 5)? * **Paper 51:** support answers with the calculation at each stage. When there are several scenarios (for example, cases in a probability question), an organised list or table makes your method clear. * **Paper 52:** use algebra to show your process, and cross out mistakes rather than writing over them. ## 8. Does presentation affect your marks? Scripts are scanned for marking. **Paper 31** warns not to overwrite work because it may be hard to read. If you run out of space, use the extra page at the back and write the question number clearly. ## How to use this list Pick the three points that match your own mistake log and make them deliberate habits for your next five past papers. Then read the examiner report for each paper you practise; it is free, and it tells you exactly what the mark scheme rewards. Back to the [Cambridge A Level Maths 9709 guide](https://mathvsarham.com/articles/cambridge-a-level-maths-9709/), or see [how to get an A* in 9709](https://mathvsarham.com/articles/how-to-get-an-a-star-in-a-level-maths/). ## Frequently asked questions ### Where can I find 9709 examiner reports? Cambridge publishes an examiner report for each series on the 9709 past papers page of its website. Each report covers every variant of every paper, with key messages and comments on each question. ### Do I lose marks for using a calculator to solve a quadratic? If you only write the roots, yes. The rubric says no marks are given for unsupported answers from a calculator, so show factorisation, the formula with values substituted, or completing the square. ### How many significant figures should I use in 9709? Give non-exact final answers to 3 significant figures (1 decimal place for angles in degrees) unless the question says otherwise, and keep at least 4 significant figures in your working. ### What does 'show that' mean in 9709? The syllabus defines it as 'provide structured evidence that leads to a given result'. Because the answer is given, every step must be shown or the marks are not awarded. ## Sources - [Cambridge 9709 Principal Examiner Report, June 2024](https://www.cambridgeinternational.org/Images/567737-june-2024-examiner-report.pdf) - [Cambridge 9709 syllabus for 2026 and 2027: Details of the assessment and command words](https://www.cambridgeinternational.org/Images/697427-2026-2027-syllabus.pdf) ## Related lectures - [Solving Past Papers | Differentiation | Class 28 | AS Level P1 9709](https://mathvsarham.com/lectures/fhS3CrFYlFs/) - [Modulus Functions, Graphs & Inequalities | Class #06 | A2 Mathematics 9709](https://mathvsarham.com/lectures/5-rziOlksuY/) ## Past papers - [9709 Mathematics](https://mathvsarham.com/past-papers/)