**Operations with Brackets** *KS3 Revision*

## What you need to know

**Things to remember:**

- We do what is inside the brackets first.

Previously we have heard the term “BIDMAS”, which tells us in what order we do our operations:

**B**rackets** I**ndices

**ivision**

D

D

**ultiplication**

M

M

**ddition**

A

A

**ubtraction**

S

S

** **

Here, we will focus on brackets. Because brackets are at the top of the list, this tells us that we have to do what is in our brackets first.

*Find the value of the following expression*

(11-3)\div2

Reading down our BIDMAS list we can see that we have to do the brackets first.

11-3=8

(11-3)\div2=8\div2

And now, we can just do the division as normal

8\div2 =4

(11-3)\div2=4

But, what happens if we have two brackets?

*Find the value of the following expression*

* *

(12+5)-(3-9)

Because we have two brackets, which one do we do first?… It doesn’t matter! Let’s start with the first one.

(12+5)-(3-9) =17-(3-9)

Now we have to do the second bracket

17-(3-9)=17 - -6

And now we can do the subtractions as usual (Remember, this will become an addition)

17 - -6=17+6=23

(12+5)-(3-9)=23

Now let’s try the second bracket first.

(12+5)-(3-9) =(12+5) - -6

(12+5) - -6=17 - -6

17 - -6 = 17 +6 =23

We got the same answer!

## Example Questions

**Question 1:** Find the value of (7-3)\times5

(7-3)\times5=4\times5 =20

**Question 2:** Find the value of (8+3)+(1-7)

(8+3)+(1-7)=11+(1-7)=11+-6=11-6=5