Keystones — Lintel
Five GCSE retrieval questions · 27 April 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Express 100 as a product of prime factors
Answer: 2² × 5² -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 20 and 3x - y = 19
Answer: x = 7, y = 2 -
3. Geometry Pythagoras — short side
Find b if a = 13cm and c = 21cm
Answer: 16.49cm -
4. Ratio Combining two ratios
a:b is 2:3 and b:c is 4:3. Find a:b:c.
Answer: 8:12:9 -
5. Statistics Expected frequency
A fair coin is flipped 186 times. How many heads would you expect?
Answer: 93