Interesting Things with JC #266: "Kaprekar's Routine” - In 1949 Dattathreya Ramchandra Kaprekar was a recreational mathematician ahead of his time. He had a passion for numbers. He was experimenting with 4-digit numbers, routinely arranging the digits and subtracting the higher digit from the lower digit. In doing so he discovered that as you repeatedly subtract the higher number from the lower number you will always get the result of 6174.