Keystones — Lintel
Five GCSE retrieval questions · 17 June 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Express 180 as a product of prime factors
Answer: 2² × 3² × 5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 38 and 3x - y = 13
Answer: x = 7, y = 8 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 10cm, c = 27cm
Answer: 25.cm -
4. Ratio Combining two ratios
a:b is 3:4 and b:c is 4:5. Find a:b:c.
Answer: 3:4:5 -
5. Statistics Expected frequency
A bag has 3 red out of 9 balls. If you pick 112 times (with replacement), how many times would you expect red?
Answer: 37.3