Keystones — Cornerstone
Five GCSE retrieval questions · 3 February 2026 · mathsvault.uk/keystones
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1. Number Highest common factor
What is the HCF of 20 and 30?
Answer: 10 -
2. Algebra Substitution
If x = 3, calculate x² + 6x + 3
Answer: 30 -
3. Geometry Circumference of a circle
Find the circumference of a circle with diameter 18cm
Answer: 56.55cm -
4. Ratio Percentage multipliers
What multiplier represents a 36% decrease?
Answer: 0.64 -
5. Statistics Averages and range
Find the mean, median and range of: 20, 33, 22, 18, 38
Answer: Mean = 26.2, Median = 22, Range = 20