http://www.cyberglass.co.uk/FlashEx/mindreader.html
Will someone please explain to me how this works? I’m freaked out by its accuracy. Does it have something to do with where you click on the ball or how long it takes you to do math in your head?
p.s. - I looked thru the threads before i posted this but didn’t find anything, sorry if this was posted before.
This was covered in this thread.
Actually it has 2-3 times. It forces you to come to a number that is a multiple of 9, then all the multiples of 9 have the same symbol on the right. That symbol changes each time.
Something like this… your two digit number with digits x and y can be expressed as 10x + y (like 65 = 60 + 5). So you add the numbers together to get x+y then subract that from 10x + y and you get (10x + y) - (x+y) = 9x. And then they make all the numbers on the chart that are multples of 9 have the same symbol.
Got it?
Your answer always turns out to be a multiple of 9. These multiples are always assigned the same symbol (0, 9, 18, 27, 36, 45, 54, 63, 72, 81).
Click the “Try Again” button a few different times, and you will see that those numbers are always assigned the same symbol.
Nice try, but not quite 
ACK, on preview I see people replied already. Dang nabbit. And I figured it all out on my own.