The nine times table
An alternative way to multiply by nine:
1. Number your fingers, 1-10.
2. Open your palms and number fingers from left to right.
3. For example, if you want to multiply 9x3, you have to hide finger nº3.
4. All the fingers from left to nº3 indicate tens. All the fingers from nº3 to right indicate units.
5. In this case (9x3) we have 2 fingers on the left and 7 fingers on the right (27).
6. This trick is easy until 9x10. Then, it becomes a little more difficult.