Use multiplication:
9 x 7:
Line up our numbers vertically:
9 | |
x | 7 |
Current result: 7 x 9 = 63
9 | |||
x | 7 | ||
6 | 3 |
Show value = 63
Add up our results by column:
9 | |||
x | 7 | ||
6 | 3 | ||
3 |
Adding up column 1, we get: 3
Our column sum becomes 3.
9 | |||
x | 7 | ||
6 | 3 | ||
6 | 3 |
Adding up column 2, we get: 6
Our column sum becomes 6.