The kinds of mark
Every mark in a maths scheme has a letter for its type and a number for how many marks it's worth: M2 is two method marks, B1 is one independent mark. When an examiner writes A0 or M0, that mark was not awarded.
- M Method mark
- For a valid method applied to this problem: differentiating with the product rule, say, or substituting the right values into the right formula. Arithmetic and algebra slips don't normally cost an M mark, but quoting a formula without using it doesn't earn one.
- A Accuracy mark
- For a correct answer or a correct intermediate result. An A mark depends on the method mark before it: if the M mark isn't earned, the A marks that follow can't be either, even when the number happens to be right.
- B Independent mark
- For a correct result or statement that doesn't depend on a method: a correctly stated value, a correct sketch feature, a correct fact.
- DM · dM Dependent method mark
- A method mark that is only available if a particular earlier M mark was earned. Cambridge writes DM, Edexcel writes dM, and AQA writes m or dM.
- E Explanation mark
- Used by some boards, AQA for example, for a correct explanation, reason or conclusion written in words.
The abbreviations
Boards differ in capitals and the odd letter, but the ideas are the same everywhere.
- ft · FT Follow through
- Later marks can be earned using your own earlier wrong answer, as long as the later working is correct. Often written A1ft or B1FT.
- cao · CAO Correct answer only
- Only the exact answer in the scheme earns the mark: no follow-through, no near misses.
- cso · CSO Correct solution only
- The whole solution has to be free of errors to earn the mark, not just the final line.
- oe · AEF Or equivalent · any equivalent form
- Any equivalent answer is accepted: ½ for 0.5, or an unsimplified but correct expression.
- awrt · AWRT Answer which rounds to
- Any answer that rounds to the stated value is accepted, so awrt 2.35 accepts 2.3496.
- isw · ISW Ignore subsequent working
- Once a correct answer is seen, extra working after it isn't marked, so a harmless extra step can't undo the mark.
- AG Answer given
- The answer is printed in the question, so the marks are for showing every step that gets you there.
- soi · PI Seen or implied · possibly implied
- The step earns its mark even if it isn't written down, provided later working shows it must have been done.
- www · nfww Without wrong working · not from wrong working
- A correct answer only earns the mark if it didn't come from incorrect working.
- CWO Correct working only
- The mark needs correct working as well as the correct answer.
- SC Special case
- A mark for a specific, partly correct approach that the main scheme wouldn't otherwise credit.
A worked example
An example question, not from a real paper: find the gradient of the curve y = x² sin x at the point where x = π. [4 marks]. The scheme gives M1 for using the product rule, A1 for the correct derivative, M1 for substituting x = π, and A1 cao for −π².
- dy/dx = 2x sin x + x² cos xM1A1Product rule used and both terms correct.
- at x = π: 2π(0) + π²(1)M1Substitution earns the method mark, but cos π is −1, not 1.
- gradient = π²A0The answer is cao: it had to be −π², so the accuracy mark is lost.
3 out of 4. The method was right from start to finish, and the only mark lost was an accuracy mark for one trig value. Writing cos π = −1 on its own line before substituting makes that kind of slip much harder to miss.
Now suppose part (b) asks for the equation of the tangent at x = π, and the scheme gives M1 for y − 0 = m(x − π) using their gradient and A1ft for the answer. Using m = π², the student writes y = π²(x − π) and gets both marks: follow-through means one early slip isn't paid for twice.
Reading a paper code
Cambridge paper codes carry the syllabus, the paper and the variant: 9709/32 is syllabus 9709 (AS & A Level Mathematics), Paper 3, variant 2. Variants are different versions of the same paper set for different time zones, so make sure your mark scheme matches the variant as well as the paper. See the subject pages for the papers in each syllabus.
Using mark schemes when you revise
- 01Sort lost marks into M and A. Lost M marks mean the method needs work, so go back to the topic. Lost A marks mean slips, so practise accuracy: exact values, signs, and checking the last line.
- 02Treat AG questions as proofs. The answer is already on the page, so every mark is for the steps. Skipping one to reach the printed answer usually costs a mark.
- 03Don't round early. Cambridge asks for non-exact answers to 3 significant figures (1 decimal place for angles in degrees) unless the question says otherwise. Keep more figures than that in your working, or the final answer can drift outside the accepted range.
- 04Give one final answer. isw protects a correct answer from harmless extra working, but if you leave two different answers, examiners generally won't pick the right one for you.
Let Method read the scheme for you
Method marks your handwritten working with exactly these codes: M, A and B marks beside each line, follow-through where the scheme allows it, and a short note on every mark you lost. See how the AI marking works.