The Mystery of Number 9

Let’s play with to find some mystery

1. Numbers in each multiplication of nine, when added together the end result is always nine
example:
1 x 9 = 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
10 x 9 = 90 —> 9 + 0 = 9
etc. …

This also applies even to a complex multiplication.
sample (random):
638 x 9 = 5742 —> 5 + 7 + 4 + 2 = 18 —> 1 + 8 = 9
23477 x 9 = 211293 —> 2 + 1 + 1 + 2 + 9 + 3 = 18 —> 1 + 8 = 9
etc. …

2. Each number is not divisible by nine, then the numbers behind the comma the results will be repeated
example:
8 / 9 = 0.88888888888888………
23 / 9 = 2.55555555555555………
56768231 / 9 = 6307581.22222222………

3. Multiplication with the number that composed of the same digit
example:
33 x 9 = 297 —> 3 x 9 = 27 put 9 (1 times) in the middle of 2 and 7, so the result 297
444 x 9 = 3996 —> 4 x 9 = 36 put 9 (2 times) in the middle of 3 and 6, so the result 3996
5555 x 9 = 49995 —> 4 x 9 = 36 put 9 (3 times) in the middle of 4 and 5, so the result 49995
etc. …

4. If 12345679 (remember without the number 8) multiplied by 1-9 multiples of 9 then the result must contain the numbers over and over
example:
12345679 x 9 = 111111111
12345679 x 18 = 222222222 —> 12345679 x 9 x 2
12345679 x 27 = 333333333 —> 12345679 x 9 x 3
12345679 x 36 = 444444444 —> 12345679 x 9 x 4
.
.
.
12345679 x 81 = 999999999 —> 12345679 x 9 x 9

That’s all, maybe next time i will add some more fun with 9. Cheers.