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How to Regroup Numbers in Addition

In a two-digit number, such as 65, the first number, 6, is in the tens place and the second number, 5, is in the ones place. These designations come from the fact that the 5 is also 1 + 1 + 1 + 1 + 1 and the 6 is really 60 or 6 * 10. Adding two-digit numbers may require regrouping, or carrying, of digits from the ones to the tens.

Instructions

- 1
  Write out the addition problem 66 + 45 vertically, with 66 on top so that the ones column contains 6 and 5, and the tens column contains 6 and 4.
- 2
  Add the ones column: 6 + 5 = 11. Note that there's not enough space in the ones answer space to hold a two-digit number. Write the ones of the answer, 1, under the ones column. Write the other 1, which is really 10, at the top of the tens column to be added.
- 3
  Add the tens column, including the regrouped 1: 1 + 6 + 4 = 11. Note that because there's no further addition to the left of the tens column, there is room for this full answer. After writing 11 in front of the 1 that is under the ones column, you will see that the final answer as 111.

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