Kaprekar's Constant

Video Description

Dattatreya Ramachandra Kaprekar discovered 6174 as the magical constant for 4-digit numbers. If we construct the largest 4-digit number using only the digits of any chosen 4-digit number, and then construct the smallest using the same digit, the difference should yield 6174. Otherwise we repeat the process with the new number (difference). After a maximum of 7 attempts, we will arrive at 6174 where the process will constantly yield 6174. Read more in books and encyclopedias.