this is just creapy

[Masamune]

http://www.cyberglass.co.uk/FlashEx/mindreader.html

can anyone figure out how this works?

[Saffith]

Yes.

First of all, notice that the symbols change every time. If you use the same number every time, it'll give you a different symbol. Makes it seem different, is all.

Secondly, notice that any two-digit numer minus the sum of its digits is a multiple of 9.
e.g.
15-6=9
47-11=36
77-14=63
There's a list of every number from 0 to 99, but most of them will never come up.

Finally, notice that every multiple of 9 has the same symbol. Voila.

[Paradox]

anything you pick will end up being a multiple of nine. every multiple of nine there has the same symbol.

EDIT: blah, two minutes late.

[Maverik X]

Damn. Beat me to it. Pretty simple when you get down to it, though. *gloating* I got it right away.

[Beldaran]

That is still really awesome.

[ShyGuy0824]

before I noticed the symbols change, I was like, "what the f?"

Still, pretty funny for the memory-inclined

[Rijuhn]

It still has guessed everything right for me so far. Incrediable.

[DarkDragon]

Originally posted by Saffith
Yes.
Secondly, notice that any two-digit numer minus the sum of its digits is a multiple of 9.

Right. If a and b are the two digits of the number 10a+b, then what the mind reader asks you to do is to evaluate
10a+b - (a+b) = 10a + b - a - b = 9a, which is obviously a multiple of 9.

To make the trick a bit less obvious, they should rearrange *all* the symbols after each refresh, instead of just the multiples of nine.

[Masamune]

i just figured it out last night. and your all right. first i wanted to know why you had to do all that subtracting. then mr cow said something about multiples of nine. i checked all the numbers that are multiples of nine and they all have the same symbol. ^_^

[TheGeepster]

Actually, you can take any positive integer (no matter how big), and subtract from it the sum of its digits, and you'll get something divisible by 9. As a matter of fact, a check for divisibility by 9 is to add the digits of a number together and if the answer is divisible by 9, so is the original number. If not, whatever the remainder of the sum is, is the remainder of the original number when divided by nine.

[Ich]

It works if you have math skills. I couldn't get it to work half the time.

[mike5000]

Either im really stupid or it just got mine wrong LOL

{edit} I am doing Nothing wrong and it got mine wrong again! this thing sucks. (yes i used a calculator!)

[KINGOFALLME2]

I dunno but i suck at math!

[carrot red]

I suck at math too, but I got this one right.:shrug:

[KINGOFALLME2]

Come to think of it......it's a bit confusing when you look at all these ways to do math. And you wonder how they came up with this shit Doncha ever think that? Like...HOW ON THE HELL DID THEY DO THAT? I do

[Maverik X]

I wouldn't be surprised if there is some underlying flaw in it. I once figured out how to make a magic trick fail by doing a certain thing. But, I don't think that there is one in this case...

[Ultra22Lemming]

Heh, there's a bunch of tricks like that. It's not anything new or special.