How to add two two-digit numbers (for example 45 + 53).

- Place one number above the other number so that the tens' place digits and ones' place digits are lined up.
Draw a line under the bottom number.
45
__53__

- Add the two ones' place digits (5 + 3 = 8).
45
__53__
8

- Add the numbers in the tens' place column (4 + 5 = 9) and place the answer below the line and to the left of the ones' place sum.
45
__ 53__
98