Always End With 1089

Add two number together and always end with 1089.

Here is How:

Pick a three digit number.
The three numbers used
must be different
*. i.e. 123
Reverse that number.
123 becomes 321
Take the smallest three digit
number from the largest.
321 - 123 = 198
Take the answer and reverse
that number. 198 becomes 891
Add that number to the
answer of the subtraction.
891 + 198 = 1089

The answer will be 1089!

So Why does it do this?
Find out here


A Little Footnote

But I ended with 198 not 1089 ... !

This happens if you pick a number like 546.

546 goes like this: 645-546=99, then 99+99=198.

BUT if you assume that 099 is a 3 digit number, you will get:
990-099=891, and 891+198=1089

*If you don't pick three different numbers then this might happen:
343-343=0, 0+0=0