Break apart addition is a strategy where you separate one number into smaller parts to make adding easier. In two-digit plus one-digit problems, you always break apart the smaller number.
Breaking apart makes addition easier by creating a friendly number (a multiple of ten).
Use the break apart strategy when adding a two-digit number and a one-digit number. Look for the distance to the next multiple of ten in the larger number.
If the one-digit number is larger than the number of ones needed to reach the next ten, break it apart.
Here are some examples showing how to break apart the one-digit number to make a new ten.
This method makes mental math easier because you add to a friendly number first, then add what is left.
Breaking apart numbers is not the only way to add, but it is a powerful strategy for solving problems quickly in your head.
This strategy builds number sense and prepares you for more advanced math.