Keystones — Lintel
Five GCSE retrieval questions · 18 March 2026 · mathsvault.uk/keystones
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1. Number Error intervals
22 is rounded to the nearest integer. What is the error interval?
Answer: 21.5 ≤ x < 22.5 -
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 13cm
Answer: 132.73cm² -
4. Ratio One amount as a percentage of another
Express 65 as a percentage of 209
Answer: 31.1% -
5. Statistics Averages and range
Find the mean, median and range of: 78, 18, 89, 93, 42, 93, 50, 35, 76
Answer: Mean = 63.8, Median = 76, Range = 75