Keystones — Lintel
Five GCSE retrieval questions · 19 March 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 99.2 (to dp). State the error interval
Answer: 99.15 ≤ x < 99.25 -
2. Algebra Expanding two brackets
Expand: (x - 6)(x - 7)
Answer: x² - 13x + 42 -
3. Geometry Area of a circle
A circle has area 452.4cm². Find its radius (dp)
Answer: 12cm -
4. Ratio One amount as a percentage of another
Express 39 as a percentage of 180
Answer: 21.67% -
5. Statistics Averages and range
Find the mean, mode, median and range of: 32, 22, 45, 22, 11
Answer: Mean = 26.4, Mode = 22, Median = 22, Range = 34