Keystones — Lintel
Five GCSE retrieval questions · 10 May 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 81.9 (to dp). State the error interval
Answer: 81.85 ≤ x < 81.95 -
2. Algebra Expanding two brackets
Expand: (x + 7)(x - 6)
Answer: x² + x - 42 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 21cm
Answer: 346.36cm² -
4. Ratio One amount as a percentage of another
Express 47 as a percentage of 299
Answer: 15.72% -
5. Statistics Averages and range
Find the mean, median and range of: 26, 27, 40, 38, 65, 59, 30, 100, 51
Answer: Mean = 48.4, Median = 40, Range = 74