Keystones — Lintel
Five GCSE retrieval questions · 30 January 2013 · mathsvault.uk/keystones
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1. Number Converting to standard form
Write 0.000078 in standard form
Answer: 7.8 × 10-5 -
2. Algebra Factorising monic quadratics
Factorise: x² - 3x - 28
Answer: (x + 4)(x - 7) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 12cm, angle = 55°. Find opposite. Give your answer to 2 decimal places
Answer: 17.14cm -
4. Ratio Mixed ratio problems
Simplify: 18:9:12
Answer: 6:3:4 -
5. Statistics Mean
The mean of 6 numbers is 30. If 5 of them are 20, 26, 17, 28, 31, what is the missing number?
Answer: 58