Keystones — Lintel
Five GCSE retrieval questions · 3 October 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 79.9 (to dp). State the error interval
Answer: 79.85 ≤ x < 79.95 -
2. Algebra Expanding two brackets
Expand: (x - 4)(x - 5)
Answer: x² - 9x + 20 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 16cm
Answer: 201.06cm² -
4. Ratio One amount as a percentage of another
51 out of 87 students passed. What percentage passed?
Answer: 58.6% -
5. Statistics Averages and range
Find the mean, mode, median and range of: 18, 47, 38, 20, 38
Answer: Mean = 32.2, Mode = 38, Median = 38, Range = 29