Keystones — Lintel
Five GCSE retrieval questions · 20 June 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Express 200 as a product of prime factors
Answer: 2³ × 5² -
2. Algebra Linear simultaneous equations
Solve: 5x + 4y = 23 and 2x + y = 8
Answer: x = 3, y = 2 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 20cm, c = 34cm
Answer: 27.5cm -
4. Ratio Combining two ratios
a:b is 2:3 and b:c is 3:4. Find a:b:c.
Answer: 2:3:4 -
5. Statistics Expected frequency
A bag has 4 red out of 11 balls. If you pick 94 times (with replacement), how many times would you expect red?
Answer: 34.2