I find numbers quite fascinating. Have a look at the magic pyramid. That’s probably the most mind blowing of all examples. Here’s my second favourite, which also uses the properties of the number 9 –

Multiplying by 9 with the fingers

Let’s say you want to multiply 9 times 3. Hold your hands up and bend the third finger. The answer is the remaining fingers.

Here’s another example – 9 x 9

And a last one – 9 x 5

Of course, we could always learn our 9 times table!