Do you know what's the magic number?

The number 1089 is known as the magic number. Do you know why? 

To better understand why the number 1089 is the magic number, I'll ask you to choice any number that is composed of 3 different digits. For example, 286. 

Considering the number 286, you begin by writing 286 backwards. Then subtract the smaller number to the larger number: 

682-286 = 396 

Then you write the result backwards, and add up the two numbers: 

396 +693 = 1089 ---- magic number 

Fantastic, isn't it? 1089 is the magic number, and it works with all numbers composed by 3 distinct digits. But beware, if in the first step, the difference is, for example 099, when reverse that number you must count with the zero. In this case, 

453-354 = 099 

099 + 990 = 1089