Keystones — Lintel
Five GCSE retrieval questions · 4 August 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Write 48 as a product of its prime factors
Answer: 2⁴ × 3 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 28 and 3x - y = 20
Answer: x = 8, y = 4 -
3. Geometry Pythagoras — short side
Find b if a = 5cm and c = 15cm
Answer: 14.14cm -
4. Ratio Combining two ratios
a:b is 1:2 and b:c is 4:7. Find a:b:c.
Answer: 2:4:7 -
5. Statistics Expected frequency
A bag has 4 red out of 9 balls. If you pick 102 times (with replacement), how many times would you expect red?
Answer: 45.3