GCSE(F),

Adding, Subtracting, Multiplying and Dividing are **operators**: they perform actions on numbers. Numbers may also have **indices** - these control operations such as squaring and square rooting. **Brackets** () are used to control the order in which calculations take place.

Each operation has a priority:

• Brackets are always calculated first;

• Indices - such as 3^{2} - are calculated next;

• Divide - is next;

• Multipy (has the same priority as Division);

• Add - is then next;

• Subtract - (same priority as Addition).

This is known as **BIDMAS** (taking the first letter of each operation); sometimes it is also known as **BODMAS**.

When there is a mixture of operations in a calculation, the sequence of operations must be carried out in BIDMAS order.

1. Ellie has calculated 4 + 6 ÷ 2 = 5. Is she correct?

Answer: No

BIDMAS: Do the division first: 6 ÷ 2 = 3, then the addition 4 + 3 = 7.

2. Put in brackets to make this calculation correct: 3 + 4^{2} = 49

Answer: (3 + 4)^{2} = 49

Put brackets before the 3, and between the 4 and ^{2}.

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