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