GCSE exam technique for maths
Maths · GCSE · The School
Command words decide the work
"Work out" wants the answer with working. "Show that" wants you to reach a GIVEN result — start from the other end and meet it. "Prove" needs a general argument, not one example. "Give a reason" needs a sentence. The mark allocation tells you the depth: 1 mark is a line, 4 marks is four visible steps.
Method marks are most of the paper
A wrong final answer with correct working usually scores most of the marks; a correct answer with no working can score one. So write every stage, keep it in order, and never rub out a wrong attempt — cross it through with one line, because uncrossed work is marked and might be the version that earns marks.
The last thirty seconds
Before moving on: does the answer have units? Is it a sensible size (an estimate check)? Did you answer what was asked — the perimeter, not the area; x, not the angle? Have you rounded as instructed (2 d.p., 3 s.f.)? These four checks recover more marks per minute than any revision technique.
"A rectangle is 7 cm by 4 cm. Work out its perimeter. (3 marks)" ANSWER A: "22 cm" — correct, one mark, because there is no method to credit. ANSWER B: "7 + 4 = 11; 11 × 2 = 22; perimeter = 22 cm" — three marks. Now suppose the arithmetic slipped and you wrote 21 cm. Answer A scores zero. Answer B still scores two, because both method steps are visible. Same knowledge, three marks apart.
Spend time where the marks are
A rough rule for a maths GCSE paper is about a minute and a bit per mark, so a 6-mark question deserves roughly the time of six 1-mark ones — if you are still stuck after that, move on and come back at the end rather than losing time you need elsewhere. Marks are not weighted by difficulty on the page, only by number, so a fiddly 2-mark question is worth exactly as much as a straightforward one.
Check by estimating
Round everything to one significant figure and redo the calculation roughly. If the estimate and the answer differ by a factor of ten, a decimal point or a unit has gone astray. It takes seconds and catches the errors that are otherwise invisible.