Keystones — Lintel
Five GCSE retrieval questions · 4 May 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 71.4 (to dp). State the error interval
Answer: 71.35 ≤ x < 71.45 -
2. Algebra Expanding two brackets
Expand: (x - 7)(x - 3)
Answer: x² - 10x + 21 -
3. Geometry Area of a circle
A circle has area 254.5cm². Find its radius (dp)
Answer: 9cm -
4. Ratio One amount as a percentage of another
Express 28 as a percentage of 164
Answer: 17.07% -
5. Statistics Averages and range
Find the mean, mode, median and range of: 40, 34, 40, 24, 40
Answer: Mean = 35.6, Mode = 40, Median = 40, Range = 16