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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Operations, inverses and priority
Use inverse operations to undo a calculation: addition is undone by subtraction, multiplication by division, and taking a reciprocal reverses a non-zero number. Cancel common factors when appropriate. Follow the conventional order of operat
Use inverse operations to undo a calculation: addition is undone by subtraction, multiplication by division, and taking a reciprocal reverses a non-zero number. Cancel common factors when appropriate. Follow the conventional order of operations: brackets first, then powers and roots, then multiplication and division from left to right, and finally addition and subtraction from left to right.
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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