Once we are confident with addition and subtraction, we can use them in everyday life.

This might include calculating the cost of a number of items in a shop or working out how much change we should get.

We use addition and subtraction in many areas of life, sometimes not even realising we are using them.

In this activity, we are going to solve some word problems involving addition and subtraction.

Let's have a look at one:

I think of a number. I **subtract 160**. My answer is **140.** What was my starting number?

Let's put this into a number sentence:

We don't know the starting number so let's put a **?**

**?**

We know we need to subtract **160**

**? - 160 =**

We know we have an answer of **140**

**? - 160 = 140**

We can now add the **140 and 160 **to find the starting number:

**140 + 160 = 300**

We can check by putting the answer where the** ? **was.

**300 - 160 = 140**

The starting number was** 300**

We could also work it out using** inverse operation:**

The inverse (opposite) of subtraction is addition, so we do 160 + 140 = 300.

Let's have a look at another one:

I think of a number. I **add 35**. My answer is **210**. What was my starting number?

Let's put this into a number sentence:

We don't know the starting number so let's put a **?**

**?**

We know we need to add **35**

**? + 35 =**

We know we have an answer of **210**

**? + 35 = 210**

We can now **subtract the 35 from 210 **to find the starting number:

**210 - 35 = 175**** **

We can check by putting the answer where the** ? **was.

**175 + 35 = 210**

The starting number was** 175**

Or we use inverse operation. The opposite of addition is subtraction, so we do 210 - 35 = 175

Now, why don't you have a go at solving some of this style of word problem?