Keystones — Lintel
Five GCSE retrieval questions · 28 June 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 19.5 (to dp). State the error interval
Answer: 19.45 ≤ x < 19.55 -
2. Algebra Expanding two brackets
Expand: (x - 7)(x - 7)
Answer: x² - 14x + 49 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 18cm
Answer: 254.47cm² -
4. Ratio One amount as a percentage of another
37 out of 86 students passed. What percentage passed?
Answer: 43% -
5. Statistics Averages and range
Find the mean, median and range of: 91, 31, 31, 17, 29, 81, 60, 33, 46
Answer: Mean = 46.6, Median = 33, Range = 74