When you are working something out that involves more than one operation, the order in which it is carried out matters.
The agreed order is:
Brackets
Powers or indices
Division and Multiplication
Addition and subtraction
This can be remembered using the word: BIDMAS or BODMAS
However, remember that multiplication and division are equally important, so in a calculation just involving multiplication and division, you carry this out from left to right. Similarly with addition and subtraction.
Examples
6 + 9 ÷ 3 The first operation to do is division because we have no brackets or indices.
6 + 3 = 9
(6 + 9) ÷ 3 This time, we have brackets, so do those first.
15 ÷ 3 = 5
15 - 4 × 2 This time, we have no brackets, indices or division, so we multiply first.
15 - 8 = 7
(15 - 4) × 2 Here, we do brackets first.
11 x 2 = 22
4 × 32 = 4 × 9 = 36 This time, we do the power first.
4 x 9 = 36
(4 × 3)2 This one needs us to do the brackets first.
122 = 144
14 - 4 + 5 This time, we have only addition and subtraction. This means that they are equally important, so we do it left to right.
10 + 5 = 15
That's lots of examples to work through. Hopefully, they have given you a good overview of how to tackle the order of operations.
Are you ready to have a go at some questions yourself?