How they hell does this work?

[rockman]

********WARNING****
*******Math Ahead****

It is simply a algebra equation...
You can see it like this. Any two digit number can be multiples of our base 10 system. Such as 32 is 3*10+2.

Now since the puzzle is telling you to split up the number, they can be represented by letters. x and y; where x is 3 and y is 2.

So it now would read x*10 + y (which is the original number)
Then the puzzle tells you to add the digits together. x+y
Then to subtract that sum from the original number.
Which is

(x*10 + y) - (x+y)
Which also reads

10x - x+y-y = 9x

Therefor the answer of any two digit number will be a multiple of nine.

[Ballss]

what rockman said. Plus all the multiples of nine are the same symbol. And it changes everytime.

It doesn't "know" what number you're thinking of.

[ewaaser]

Now I got it.....didn't catch the multiples of 9 all being the same symbol and changing each time.

[ynot]

If you add the 2 digits in the answer for any multiple of you get 9
is a majical number