If
someone ever told you that the answer to the ultimate question of life,
the universe and everything is "42", tell them that is wrong.
The answer is "**6174**" and here's why (and prepare
to get your mind blown):

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.

Pretty cool, huh?

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).

See also: Math T-shirts at the NeatoShop

Newest 5 CommentsAbusive comment hidden.(Show it anyway.)7072 --> 7432 --> 5074 --> 7072...

or

7252 --> 5254 --> 3076 --> 7252...

(there may be more...these are the only ones I've found so far).

Abusive comment hidden.(Show it anyway.)Abusive comment hidden.(Show it anyway.)the sum of the digits in the answer always add up to nine

3x9= 27 2+7 =9

123x9= 1107 1+1+0+7 =9

Abusive comment hidden.(Show it anyway.)Here's the maths for yours either way:

5834 is 8543-3458=5085

5085 is 8550-0558=7992

7992 is 9972-2799=7173

7173 is 7731-1377=6354

6354 is 6543-3456=3087

3087 is 8730-0378=8352

8352 is 8532-2358=(you know it) 6174.

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