Priority of Operations

Priority of Operations

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 32 - 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.

Examples

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 + 42 = 49

Answer: (3 + 4)2 = 49

Put brackets before the 3, and between the 4 and 2