6174

Math makes my head hurt.

Weird math stuff like this really makes my head hurt. I'm surprised the below hasn't turned up on LOST in some way.

Take any number with 4 non-repeating digits. Say 1562.

Step 1: Arrange the number in ascending and then descending order
Step 2: Subtract the smaller number from the bigger number

6521 - 1256 = 5265

Repeat the steps:

6552 - 2556 = 3996
9963 - 3699 = 6264
6642 - 2466 = 4176
7641 - 1467 = 6174

Try any 4-digit number with non-repeating digits, and you'll *always* get 6174.

Creepy.

6174 is known as Kaprekar's constant. The math operation above, discovered by Indian mathematician D.R. Kaprekar, will reach 6174 after at most 7 steps (if you did more than 7 iterations, check your arithmetics).

[Found Here]