Using Models to Understand Addition

Question

What is the sum of 22 and 17?

Notice that the 2 ones and the 7 ones make 9 ____

And notice that the 2 tens and the 1 ten combine to make 3 tens, which is the same as _____

So now we have 3 tens and 9 ones, which is the same as 30 plus 9, and that gives us our sum of _____

Answer 1

To find the sum of 22 and 17:

1. Breakdown the numbers:

   • 22 consists of 2 tens and 2 ones.
   • 17 consists of 1 ten and 7 ones.

2. Add the ones:

   • 2 ones (from 22) + 7 ones (from 17) = 9 ones.

3. Add the tens:

   • 2 tens (from 22) + 1 ten (from 17) = 3 tens.

4. Combine the results:

   • 3 tens and 9 ones can be expressed as 30 (from 3 tens) plus 9 (from 9 ones).
   • Therefore, 30 + 9 = 39.

So, the sum of 22 and 17 is 39.