How to add two two-digit numbers (for example 45 + 67) with paper and pencil.

• Write one number above the other so that the tens' place digits and ones' place digits are lined up. Draw a line under the bottom number.

45
67

• Add the ones' place digits. (5 + 7 = 12). This sum is a two-digit number so place a one above the tens' place column and place the two below the line in the ones' place column.

1
45
67
 2

• Add the numbers in the tens' place column (1 + 4 + 6 = 11) and place the answer below the line and to the left of the ones' place sum.

 1
 45
 67
112