Use Partitioning to Add Two-Digit Numbers

In this activity, we will be adding together two-digit numbers. 

 

Two-digit numbers have a tens digit and a ones digit. 

To add them together, it is useful to partition each number into its tens and ones. 

 

Let's see how this works.

 

34 + 43 = ?

 

To add together 34 and 43, we first partition the numbers. 

34 becomes 30 and 4.

43 becomes 40 and 3

 

Then, we add together the tens and the ones.

30 + 40 = 70

4 + 3 = 7

 

Lastly, we add together the two smaller totals, to make a grand total. 

70 + 7 = 77

 

34 + 43 = 77

 

 

Let's try an example question together.

 

Example

Add the numbers together.

62 + 26 = ?

 

Answer

First, we partition the numbers.

62 becomes 60 and 2.

26 becomes 20 and 6

 

Now, we add together the tens and ones.

60 + 20  = 80

2 + 6 = 8

 

Then, we add them to find the total.

80 + 8 = 88

62 + 26 = 88

 

Now it's your turn to try some questions like this.