The Magic of Nines

Nine is a really cool number.

I learned some pretty cool tricks in grade school, and they’ve always hung with me. So, today I will show you some interesting facts about them.

Let’s take a look at this:

1 X 9 = 9
2 X 9 = 18 (1+8=9)
3 X 9 = 27 (2+7=9)
4 X 9 = 36 (3+6=9)
5 X 9 = 45 (4+5=9)
Now notice this. You get reciprocals (the digits turn around) for the product or answer
6 X 9 = 54 (5+4=9)
7 X 9 = 63 (6+3=9)
8 X 9 = 72 (7+2=9)
9 X 9 = 81 (8+1=9)

And now for casting out nines