This is an interesting graph. How to understand this: https://www.youtube.com/watch?v=AeqK96UX3rA
This graph is based on taking a number and a substring of that number - for example, 2763 and 276. You can double this string in place (552) and attach the remaining digit(s). This will result in 5523. If your substring is even, you can divide by two as well.
