If you noticed that the symbols corresponding to the #'s change each time...........that has a big part to do with it.
Also, for the #'s 10-19, you will get 9. 10 - 1 = 9, 11 - 2 = 9.
For the #'s 20 - 29, you will get 18. 20 - 2 = 18, 29 - 11 = 18
For the #'s 30 - 39, you will get 27. 30 - 3 = 27, 39 - 13 = 27.
So, for each set of #'s that you go up, you raise the answer by a power of 3.
I just went back and did it. When you look, notice the symbol for each of the powers of 3.........that being 9, 18, 27, etc., etc.
