Addition with regrouping, step by step

Regrouping — carrying a ten to the next column.

The question

12 + 38

12=10+2
38=30+8
10+30=40
2+8=10
40+10=50
  1. 12 + 38, written across the line — so split each one into its tens and its ones, and add like with like.
  2. The tens together: 10 + 30 = 40.
  3. The ones together: 2 + 8 = 10. That is over ten, which is fine — it is a whole ten and some more, and it goes back in as one.
  4. Put the two parts back together: 40 + 10 = 50.

How it works.

  1. 01

    12 + 38, written across the line — so split each one into its tens and its ones, and add like with like.

  2. 02

    The tens together: 10 + 30 = 40.

  3. 03

    The ones together: 2 + 8 = 10. That is over ten, which is fine — it is a whole ten and some more, and it goes back in as one.

  4. 04

    Put the two parts back together: 40 + 10 = 50.