Keystones — Lintel
Five GCSE retrieval questions · 25 January 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 + 3y = 22 and 4x + 3y = 26
Answer: x = 2, y = 6 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 12cm, c = 25cm
Answer: 21.9cm -
4. Ratio Combining two ratios
a:b is 3:4 and b:c is 2:3. Find a:b:c.
Answer: 3:4:6 -
5. Statistics Expected frequency
A fair coin is flipped 68 times. How many heads would you expect?
Answer: 34