Keystones — Lintel
Five GCSE retrieval questions · 22 September 2026 · mathsvault.uk/keystones
-
1. Number Product of primes
Express 100 as a product of prime factors
Answer: 2² × 5² -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 21 and 3x - y = 15
Answer: x = 6, y = 3 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 18cm, c = 36cm
Answer: 31.2cm -
4. Ratio Combining two ratios
a:b is 2:3 and b:c is 1:2. Find a:b:c.
Answer: 2:3:6 -
5. Statistics Expected frequency
A fair coin is flipped 80 times. How many heads would you expect?
Answer: 40