Vertical subtraction, step by step
Written subtraction is easier to get right when the digits already line up.
The question
30 − 3
210 30 3 27
- 30 − 3, written in columns. Start at the RIGHT, with the ones.
- 0 is too small to take 3 from, so a ten comes across from the left: the ones now holds 10. 10 − 3 = 7.
- This column gave a ten to the right, so it is now 2, not 3. 2 − 0 = 2.
- That is the whole sum: 30 − 3 = 27.
How it works.
- 01
30 − 3, written in columns. Start at the RIGHT, with the ones.
- 02
0 is too small to take 3 from, so a ten comes across from the left: the ones now holds 10. 10 − 3 = 7.
- 03
This column gave a ten to the right, so it is now 2, not 3. 2 − 0 = 2.
- 04
That is the whole sum: 30 − 3 = 27.