Fun With Numbers!

I like to teach Math tricks because I think Maths can be also funny :)

Multiplication tables are often hard to learn for children, so tricks can be used to help.

The most difficult multiplication seems to be 7x8. It can be learnt this way: 5-6-7-8 -> 56 = 7x8 -> 7x8 = 56

Someone found multiplication table of 9 difficult, but when I was a child, my mom taught me this trick, the "stairways" or the "elevator":

The digit of the tens goes up, the digit of the units goes down.

Now we're making a joke to the 8. Lets pretend 8 doesn't exist and write down all the digits from 1 to 9. You'll get this number:

12345679

Now multiply this number for one of the results of the multiplication table of the 9, from 9 to 81. You'll obtain a number that's have only one digit, and that the one you multiply the 9 for in the number you choose.

This is simpler to understand just looking to the image. :)

This is not mine, but I think it's wonderful: Song from π!

Pythagoras's Theorem demonstrated with water (not mine), for older pupils: