How to teach carrying in addition (regrouping), step by step
A step-by-step way to explain carrying (regrouping) in addition, with worked examples, the mistakes kids make most, and short ways to practice at home.
Skill guide · Grades 1–4
Addition with regrouping (carrying)
What regrouping in addition means, a worked three-digit example, the mistakes kids make most, and short ways to practice carrying at home.
What it is
Regrouping, often called carrying, happens when a column adds up to 10 or more. Each column can only hold one digit, so ten ones are traded for one ten and written above the next column to the left. The same goes for ten tens becoming one hundred.
Children usually meet it with two-digit numbers in second grade, use it with three-digit numbers in third grade, and are expected to add any whole numbers with the standard method by fourth grade.
A worked example
586 + 347 = 933
1
1
5
8
6
+
3
4
7
9
3
3
Every step, the way the pad explains it
- Add the ones: 6 + 7 = 13. Write 3, carry 1.
- Add the tens (with the carry): 1 + 8 + 4 = 13. Write 3, carry 1.
- Add the hundreds (with the carry): 1 + 5 + 3 = 9. Write 9.
- 1Line up the numbers on the right, ones under ones.
- 2Ones: 6 + 7 = 13. Write 3, carry 1 to the tens.
- 3Tens: 1 + 8 + 4 = 13. Write 3, carry 1 to the hundreds.
- 4Hundreds: 1 + 5 + 3 = 9. Write 9.
- 5The answer is 586 + 347 = 933. Estimate to check: about 590 + 350, which is about 940.
Common mistakes
Writing the whole two-digit sum under one column (13 instead of 3).
Remind them each column holds one digit. The ten has to move left.
Writing the carry but not adding it.
Have them touch the carried digit with the pencil before adding each column.
Starting on the left.
Carries move left, so we start at the ones and work left.
Numbers not lined up.
Use graph paper or turn lined paper sideways so the lines make columns.
Grade range and practice
Usually taught in grades 1–4. Schools order topics a little differently, so your child’s class may meet it earlier or later.
- Mix problems with no carry, one carry and two carries, so your child has to decide each time.
- Ask for an estimate before every problem.
- Make a mistake on purpose and let your child find it.
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