Keystones — Lintel
Five GCSE retrieval questions · 16 August 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 23 (to dp). State the error interval
Answer: 22.95 ≤ x < 23.05 -
2. Algebra Expanding two brackets
Expand: (x + 3)(x - 3)
Answer: x² + 0x - 9 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 24cm
Answer: 452.39cm² -
4. Ratio One amount as a percentage of another
44 out of 80 students passed. What percentage passed?
Answer: 55% -
5. Statistics Averages and range
Find the mean, median and range of: 73, 20, 65, 45, 16, 23, 87, 56
Answer: Mean = 48.1, Median = 56, Range = 71