LOL...Welcome to the magic of the nines. Any multiple of nine is composed of digits that also add up to a multiple of nine.
I think the trickiest thing they did was to change the symbol associated with the multiples of nine each time. Click the crystal ball a few times and watch the symbols associated with the numbers. You'll always get the symbol associated with 9, 18, 27, etc, but the symbol-matchings change each round.
SNG