http://www.cyberglass.co.uk/FlashEx/mindreader.html
I give up, I know the answer is going to elicit use of the smack smilie, but what the heck is going on here?
Think about how the target number is chosen.
Look at the symbols next to all the multiples of 9: 9, 18, 27…
Don’t know how it does it but just from my initial observation the numbers and symbols switch everytime you do it. I’ll keep looking for the trick but in the meantime it is freakin’ cool.
Well, it didn’t guess my number. Anyone else get it to work? It may just be random.
Took me a second, since I’m not that great at math, but I’ve figured it out. Following the formula they give you, you’ll always end up with a certain set of numbers out of the 99. Those numbers don’t change.
The trick comes in the changing of the symbols every time you try it. The symbols for numbers 0, 9, 18, 27, etc will always be the the same for each individual round you play.
And on preview, Lego got it. Damn my slow typing.
That is too freaky.
Think of it this way: A number, n, can be expressed as two digits, x (in the tens place) and y (in the ones place), such that:
n = 10x + y
The “psychic” wants you to sum those numbers and subtract it from the originial for the new number, p.
p = n - (x+y), or p = n - x - y.
Substituting in our first equation:
p = 10x + y - x - y, or
p = 9x
In other words, the psychic answer is always going to be a multiple of 9 and, sure enough, 0, 9, 18, etc. are always assigned the same symbol. 90 isn’t, but given that we’re dealing with two-digit numbers, we couldn’t land there, anyway!
Yes, but I still don’t understand something. It doesn’t always display the same symbol, so how can it guess correctly everytime? It must get it wrong sometimes.
It changes the symbols around each time you play. Notice what’s assigned to “0”, then click and see it. Repeat as necessary.
Ahh… thank you Pantellerite! Very clever.
Ahh… thank you Pantellerite! Very clever.
Heh. My sister sent me this one by e-mail, and was quite pissed off when I mailed her back in 5 minutes with an explanation. Took her 2 hours to figure out what was wrong, she couldn’t do it, so she mailed me. 
And I suck at math, by the way.
Damn, you take all the mystery out of life!
Solving Mysteries of the Universe–that’s what I get paid the big bucks for!
It took me a while to figure it out last night. It drove me crazy for a few minutes until I just decided to pick a number at random, while looking at all the numbers, and see if it could read my mind then. Imagine my surprise when the first couple of numbers I picked at random happened to be multiples of nine, anyways! I was really starting to freak. Then I decided to look and see if some symbols were duplicated, and that’s when I figured it out. Sometimes I’m a little slow.