Solve Addition and Subtraction Word Problems.

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?