http://digicc.com/fido/



how do they guess the number? hmmmmm

 

I believe, and mind you I haven't checked the validity, that the number you choose is identified by the three other numbers you put in. That is, after the subtraction process, only certain numbers will ever be together. That's why they make the distinction of making all your digits be different. 4321 - 1234 = 3087. If you put in 308, 803, 380, 830, or whatever it will know the other number is a 7 because there is no way to get 3088, 3089, or any other number with '308' in it. This is also why they say you can't circle 0, because there might be other numbers with a 387 in them.

 

GAHHH! THE ******!!!

 

Haha I did it, and they guessed the wrong one



I'm serious



Which speaks volumes of how well I follow instruction

 

damn colin, its too early for a drunkn post

 

u messed up ur math....hahaha try with a calculator

 

The answer is always going to be a multiple of 9. If you use 3 numbers they will add up to be 9, if you use 18 they will add up to be 18. All it has to do is subtract the numbers you entered and it comes up with the number you circled.



Atleast i think thats how it is done.

 

look at all you smart guys! you've all got such great answers! im jealous that i couldnt think of anything like that to explain it.