Method Marks: How to Score When Your Final Answer Is Wrong

Here is a fact that changes how you should sit a maths or science exam: in most calculation questions, the final answer is worth only one of the marks. The rest are for how you got there. A student who writes down the right number with no working can score less than a student who writes clear working and makes a slip at the very end. Once you understand why, you stop treating working as something you tidy up if you have time, and start treating it as where most of the marks actually live.

M marks and A marks

Exam boards split calculation marks into two kinds. Method marks (often written M1, M2 in the mark scheme) are awarded for using the correct process — the right equation, the right substitution, the right rearrangement. Accuracy marks (A1) are awarded for the correct final value. A typical three-mark question might be structured as two method marks and one accuracy mark. That means two-thirds of the marks are available before you have finished the arithmetic.

This is why “show your working” is not a polite request. It is the board telling you where the marks are. An answer line with a single number gives the examiner nothing to award the method marks against, so if that number is wrong, you score zero — even if your understanding was almost perfect and you simply mistyped into a calculator.

A worked example

Take a physics question: calculate the kinetic energy of a 1,200 kg car travelling at 15 m/s. The mark scheme awards three marks:

• M1 — correct equation: kinetic energy = ½ × mass × velocity²
• M2 — correct substitution: ½ × 1200 × 15²
• A1 — correct answer: 135,000 J

Now suppose a student writes the equation, substitutes correctly, but forgets to square the velocity and writes 9,000 J. Because the working is on the page, the examiner can see the equation and the substitution were right. That student scores 2 out of 3— the two method marks — despite a wrong final answer. A different student who writes only “135,000” with no working scores 3 if it is right and 0 if a calculator slip made it 13,500. The first student protected their marks. The second gambled them.

Error carried forward

There is a second reason working matters, and it is one of the most generous rules in exam marking: error carried forward, usually abbreviated ECF. When a question has several stages, a mistake in an early stage does not have to cost you the later marks. If you use your own (wrong) earlier answer correctly in the next step, the examiner can award the method marks for that step as if your earlier value had been right.

Say a chemistry calculation asks you to find moles, then use that to find mass. If you make a slip and get the moles wrong, but then multiply your wrong moles by the correct relative formula mass, the second stage still earns its marks. ECF only works if the working is visible — the examiner has to be able to follow your wrong number through to see that you used it correctly. A student who hides their working forfeits ECF entirely, because there is nothing to carry forward.

The habits that protect method marks

A few disciplines turn this from theory into marks on the page.

• Write the equation before the numbers. Even a formula on its own can earn a method mark, and it makes your substitution easier to mark.
• Never cross out working unless you are replacing it. Crossed-out working is not marked, so a panicked student who scribbles out a correct method has just deleted their own marks. If you are not sure, leave it.
• Show every substitution. The step where numbers replace symbols is where a method mark usually sits. Do not do it in your head.
• Give units and sensible significant figures. A separate mark is often reserved for the correct unit, and an answer to an absurd number of decimal places can lose the accuracy mark on its own.
• Do not tidy up at the end. Rewriting a “neat” version and rubbing out your real working is the single most expensive tidiness habit in exams.

Why practice is the only way to make it stick

Knowing about method marks and actually laying out working that captures them are different skills, and the gap only closes with practice on real questions where you can see, line by line, which marks your working earned. This is where marking against the real scheme matters: it is not enough to be told your final answer is wrong, you need to see that your M1 and M2 were awarded and only the A1 was lost — because that tells you your method is sound and the fix is a careful check, not more revision. Every calculation you practise on Exaim is marked this way, point by point, so you learn to lay out working the way the mark scheme rewards. It pairs naturally with knowing your command words: “calculate” is simply the command word that puts method marks on the table.