Keystones — Lintel
Five GCSE retrieval questions · 4 October 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 45.4 (to dp). State the error interval
Answer: 45.35 ≤ x < 45.45 -
2. Algebra Expanding two brackets
Expand: (x - 7)(x - 2)
Answer: x² - 9x + 14 -
3. Geometry Area of a circle
A circle has area 78.5cm². Find its radius (dp)
Answer: 5cm -
4. Ratio One amount as a percentage of another
Express 36 as a percentage of 211
Answer: 17.06% -
5. Statistics Averages and range
Find the mean, median and range of: 84, 61, 25, 19, 42, 24, 56
Answer: Mean = 44.4, Median = 42, Range = 65