What is the trick to multiplying 9's?

Answer 1

before i get started here's a helper fact: the finger counting is left to right. Like reading.

Easy. Put up all your fingers. Look at them...look at them....now if your problem is 9 * 3. Then you would put down your third finger counting from the left.

You should see now 2 fingers. then a space (the third finger you put down) and then 7 other fingers. Put those numbers together and....27! 9 * 3 = 27!

Next example. 9 * 7. Put your hand up again. And put down your 7th finger down. counting from the left.

You should see now 6 fingers. then a space (the 7th finger you put down) and then 3 other fingers. Put those numbers together and....63! 9 * 7 = 63!

Now try some other numbers! It only goes up to 10 though. 11 * 9 = 99 and 12 * 9 = 108!