Numbers on a clock all consist of the following amount of numbers: 3,4,5,6
These numbers will either bring you to the numbers: 3,4,5,6
Now once you get to those numbers, you will only be on the numbers of 8 or 9.
After he asks you to spell 8 or 9, the you will automatically be on 1. Since 9 has 4 letters, and 8 has 5 letters it will take you to the same number.
From there on it is exactly the same for everyone.
I apologize if I bursted anyone's bubble, but I was writing this down on here as I was figuring out the math myself. And I thought, maybe I wasn't the only one that was curious on how it works and thought I'd post it.