Addition Without Regrouping

Addition without regrouping

When you add multi-digit whole numbers without regrouping, each place-value column can be added separately and every sum stays below 10. That means there is no need to carry any digit to the next column.

Method

1. Write the numbers vertically so ones line up under ones, tens under tens, and so on.
2. Start with the ones place. Add the digits in that column.
3. Move to the next column to the left and repeat the same process.
4. Keep going column by column until all place values are added.
5. Write the answer by combining the sums from each column.

Important idea

Because there is no regrouping, each column is independent. If a column adds to 10 or more, then regrouping would be needed, so check that the problem really stays within the no-carry condition.

Quick check

Estimate whether the answer is reasonable by looking at the size of the numbers. You can also add the numbers again from right to left to confirm each column was done correctly.

Example strategy

For a problem like 243 + 156, add 3 + 6, then 4 + 5, then 2 + 1. Put the column sums together to get the final total.