Pearson Edexcel GCSE (9-1) Mathematics study guide
Structure and calculation Study Guide
Review study guide for Structure and calculation in Edexcel Mathematics.
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Structure and calculation
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Estimating powers and roots
To estimate a power or root of a positive number, locate nearby values that are easier to calculate exactly. For roots, compare the number with nearby perfect powers, such as squares or cubes, then choose an intermediate value and check its
To estimate a power or root of a positive number, locate nearby values that are easier to calculate exactly. For roots, compare the number with nearby perfect powers, such as squares or cubes, then choose an intermediate value and check its size. For powers, use a nearby convenient base and adjust the result sensibly. The estimate should lie between the corresponding nearby known values.
Counting successive choices
The product rule counts outcomes formed by a sequence of choices. Multiply the number of available options at each stage, because every option at one stage can be paired with every option at the next stage. For example, choosing 3 starters,
The product rule counts outcomes formed by a sequence of choices. Multiply the number of available options at each stage, because every option at one stage can be paired with every option at the next stage. For example, choosing 3 starters, 4 main courses and 2 desserts gives 3 × 4 × 2 = 24 possible meals. The method assumes that each stated choice can be made in combination with the choices before it.
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