Solve Addition and Subtraction Problems Using Partitioning

In this activity, we are going to look at using the written method of partitioning to help us solve addition and subtraction questions. 

 

Example 1 

32 + 12 = 

Let's have a look at a written method called partitioning to help us solve this.

Let's partition each number into tens and ones. 

 

32 = 30 + 2 

12 = 10 + 2 

 

We can use TOT to help us work it out. First, we add the tens, then we add the ones and then we add them both together to find the total: 

 

Tens: 30 + 10 = 40 

Ones: 2 + 2 = 4

Total: 40 + 4 = 44  

 

Example 2 

Using partitioning for subtraction is a little bit different. 

 

Let's have a look at how to solve this: 

48 - 12 = 

 

This time, we only partition the number that we are taking away. 

12 = 10 + 2

We start with 48 and take away the tens from 12 which is 10. 

48 - 10 = 38

 

This gives us 38, so we take 38 and take away the ones from 12 which is 2. 

38 - 2 = 36 

And there we have our answer. 

 

Go and grab yourself a pencil and paper and you can use this written method to answer these questions.