In this activity, we will work out a subtraction by counting on using a number line.

Example

Work out 332 - 153 = 

We use the number line to count up from the smaller number to the larger number.  

First step: go to the next hundred, i.e. 200 here (153 + 47 = 200)

Second step: count up in hundreds to the hundred below your given number, i.e. 300 here (200 + 100 = 300)

Third step: count up to the given number, i.e. 332 here (300 + 32 = 332)

Answer is 47 + 100 + 32 = 179

So, 332 - 153 = 179

These can be quite complicated so we'll take it slowly through some questions.