What's the correct order to do this calculation?

**3 + 7 x 10 **

If we **add **first, the answer would be 100.

But if you **multiply** first, the answer would be 73.

We need to have an order in which we all do calculations, so everyone does it the same way.

This diagram below shows the correct order in which we do calculations, starting at the top working down.

We can use **BIDMAS **to help us remember the order.

**Example: **

4 - 2 x 3

The diagram shows x comes before -, so we do 2 x 3 = 6 first.

Then we subtract, so 4 - 6 = -2

So, 4 - 2 x 3 = -2

__Example: __

3 x (4 + 5)^{2}

The diagram shows that the **brackets** are first.

4 + 5 = 9

**Indices** come next:

9^{2} means 9 x 9 = 81

Finally we do 3 **x** 81 = 243.

So, 3 x (4 + 5)^{2} = 243

__Example:__

(2 x 5) - (3 x 3) + 1

**Brackets** first: 2 x 5 = 10 and 3 x 3 = 9

There's a - and a + and they're on the same level, so we do them left to right.

10 - 9 + 1 = 2

So, (2 x 5) - (3 x 3) + 1 = 2

Happy with that?

Let's give it a go.