Keystones — Lintel
Five GCSE retrieval questions · 27 September 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Write 72 as a product of its prime factors
Answer: 2³ × 3² -
2. Algebra Linear simultaneous equations
Solve: 2x + 2y = 28 and 3x + 2y = 35
Answer: x = 7, y = 7 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 13cm, c = 22cm
Answer: 17.7cm -
4. Ratio Combining two ratios
a:b is 3:4 and b:c is 1:2. Find a:b:c.
Answer: 3:4:8 -
5. Statistics Expected frequency
A fair coin is flipped 200 times. How many heads would you expect?
Answer: 100