Addition With Regrouping

Addition with Regrouping

When adding multi-digit whole numbers, start with the ones place and move left. If the digits in one place add to 10 or more, regroup by writing the ones digit and carrying the tens digit to the next column.

Step-by-step method

1. Line up the numbers by place value. Put ones under ones, tens under tens, hundreds under hundreds, and so on.
2. Add the ones column first. If the sum is 10 or more, write the ones digit and carry the extra tens to the next column.
3. Add the tens column, including any carried number. Regroup again if needed.
4. Continue leftward until all columns are added.
5. Write the final total from left to right.

Good check

Estimate first to see whether your answer is reasonable. Then, re-add the columns or add the numbers in a different order to confirm the total. Also make sure each carried number was added to the next place value.

Common mistake to avoid

Do not forget to add the carried digit. A carry is part of the next column, not a separate number.