Lets see who will know how it works?:D

http://193.6.55.14/poen/flash/magic.swf

regardless of your choosing, the answer will always be the same, however only per game. Each new game produces a new, and different "known" answer from the previous game, however you're presented with a set of supposedly random symbols.

hmmm, it quite amazing! must break the trick to this...

THIS IS HOW IT'S DONE, SO IF YOU DON'T WANT ME TO SPOIL IT, DON'T READ IT.

Easy, with that mathematical formula, you can only get a handful of numbers. 9, 18, 27, 36...they're all multiples of 9. The "crystal ball" comes up with a different symbol every time because the chart's symbols change with it. Every multiple of nine is covered with the same symbol, and that symbol is the one that will show up. You can even see the pattern in the chart if you start at 81, and go diagonally up to the right (one over, two up) and you'll see a diagonal of the same symbols, and each one is a multiple of nine. This diagonal doesn't cover all the multiples of nine, but if you look, they're all covered.

Formula
10 --> 9
11 --> 9
12 --> 9
.
.
.
20 --> 18
21 --> 18
22 --> 18
.
.
.
30 --> 27
31 --> 27
32 --> 27
.
.
.
.
.
.
.
.
90 --> 81
91 --> 81
.
.
.
.
.
99 --> 81

EDIT: So, if the crystal ball didn't work for you, you don't know how to add and subtract :p

the answer will always be a multiple of nine...the symbols do in fact change every game, but every mutiple of nine will have the same symbol

this one's better:

http://digicc.com/fido/

Here's the answer:
It's just math, and it's programmed into the flash program...

woohoo, i'm bored....

go algebra go!