1. Pick any 3-digit number, except one that has all the same three digits (ex. 333)

2. Arrange the three digits from largest to smallest, and then from smallest to largest

3. Subtract the smaller number from the larger number

4. Take the answer and repeat steps #2 and #3

5. Repeat until you can't go any further

6. Once you can't go any further press the go button below and enter it on the next screen