Keystones — Lintel
Five GCSE retrieval questions · 20 January 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Write 90 as a product of its prime factors
Answer: 2 × 3² × 5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 22 and 3x - y = 11
Answer: x = 5, y = 4 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 24cm, c = 32cm
Answer: 21.2cm -
4. Ratio Combining two ratios
a:b is 3:5 and b:c is 5:6. Find a:b:c.
Answer: 3:5:6 -
5. Statistics Expected frequency
A fair coin is flipped 164 times. How many heads would you expect?
Answer: 82