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 with your new number (the answer):

(5265 rearranged) 6552 - 2556 = 3996

(3996 rearranged) 9963 - 3699 = 6264

(6264 rearranged) 6642 - 2466 = 4176

(4176 rearranged) 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 arithmetic).

Via

Use your equal signs more carefully, surely (5265 = 6552 - 2556 = 3996) Is not a valid equation as 5265 is not equal to 3996..

ReplyDeleteanonymous, the poster isn't insinuating 5265 = 3996; he was saying that 5265 rearranged with the greatest number at the beginning is equivalent to 6552.

ReplyDeleteYes exactly. But just to be perfectly clear, I have changed it. Thanks!

ReplyDelete7156

ReplyDelete7651-1567=6084

8640-0468=8172

8721-1278=7443

7443-3447=3996

9963-3699=6264

6642-2466=4176

7641-1467=6174

awesome stuff!

I have to agree with the first anonymous poster, If you are writing "5265 = 6552 - 2556 = 3996", the you ARE implying that 5265 IS equal to 3996, no matter what your intentions were. That is what the equality sign means.

ReplyDeleteBut the original poster have now solved the "problem" in a nice way...

I have noticed that this works so long as all 4 digits don't repeat (obviously), but even up to 3 repeating digits will produce the result of 6174. Very interesting indeed.

ReplyDelete