Black Hole Number in Mathematics

What is the Black Hole Number??

6174 is known as Kaprekar's constant after the Indian mathematician D.R.Kaprekar.

      So, why 6174  is the black hole number??

     1. Simply take 4 digit number.(At least 2 different digit)

     2. Arrange the digits in descending and in ascending order.

     3. Substract the smaller number from the bigger number.

     4. Repeat the step 2 to step 4.

      For example 6767.

      7766 - 6677 = 1089

      9810 - 0189 = 9621

      9621 - 1269 = 8352

      8532 - 2358 = 6174

      7641 - 1467 = 6174

      Not convinced yet ?

      Lets try another number : 1234

      4321 - 1234 = 3087

      8730 - 0378 = 8352

      8532 - 2358 = 6174

      7641 - 1467 = 6174

So, how about 3 digit number??

495 is another black hole number for 3 digit number.

Lets try!!

Assume we put 624 as a lucky number.

642 - 246 = 396

963 - 369 = 594

954 - 459 = 495

954 - 459 = 495

    You can try your lucky 4 digit  and 3 digit number on your own.