Keystones — Lintel
Five GCSE retrieval questions · 22 March 2026 · mathsvault.uk/keystones
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1. Number Error intervals
53 is rounded to the nearest integer. What is the error interval?
Answer: 52.5 ≤ x < 53.5 -
2. Algebra Expanding two brackets
Expand: (x + 4)(x - 8)
Answer: x² -4x - 32 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 9cm
Answer: 63.62cm² -
4. Ratio One amount as a percentage of another
Express 30 as a percentage of 228
Answer: 13.16% -
5. Statistics Averages and range
Find the mean, mode, median and range of: 10, 26, 38, 19, 26
Answer: Mean = 23.8, Mode = 26, Median = 26, Range = 28