Dividing by 9, step by step
The nines carry a check no other table has: add the digits, and if they come to nine the number divides evenly.
The question
72 ÷ 9
72÷9
9×?=72
9×8=72
72÷9=8
8×9=72
- 72 ÷ 9 means sharing 72 out equally between 9. Deal them round one at a time until they run out; the answer is how many end up in one share.
- Dealing out 72 one at a time works, and takes all day. The shortcut is the same fact read backwards: 9 shares of WHAT makes 72?
- 9 × 8 = 72. That is the one, so 72 ÷ 9 = 8.
- Worth checking, because it costs one multiplication: 8 × 9 = 72. It matches, so the answer holds.
How it works.
- 01
72 ÷ 9 means sharing 72 out equally between 9. Deal them round one at a time until they run out; the answer is how many end up in one share.
- 02
Dealing out 72 one at a time works, and takes all day. The shortcut is the same fact read backwards: 9 shares of WHAT makes 72?
- 03
9 × 8 = 72. That is the one, so 72 ÷ 9 = 8.
- 04
Worth checking, because it costs one multiplication: 8 × 9 = 72. It matches, so the answer holds.