Adding two three digit numbers (for example 529 + 733) involves several steps.

• Place one number above the other so that the hundreds, tens and ones places are lined up. Draw a line under the bottom number.

529
733

• Add the ones place digits (9 + 3 = 12). This number is larger than 10 so place a one above the tens place column and place the two below the line in the ones place column.

 1
529
733
  2

• Add the tens place digits (1 + 2 + 3 = 6) and place the answer below the line and in the tens place column.

529
733
 62

• Add the numbers in the hundreds place column (5 + 7 = 12) and place the 2 below the line and before the other number below the line. Place the 1 from the twelve above the thousands place column.

1
 529
 733
 262

• The thousands place column only has a 1 in it which should be placed below the line in the thousands place column.

  529
  733
 1262