How is it done?

Jun 4, 2005
19,723
1
0
Well, there are only so many results you can have by subtracting one number by another. It'll probably just look through a database of numbers and look for one that contains two of the numbers you've given it. The third number in that number in the database would be the one you circled?
 

Caesar

Golden Member
Nov 5, 1999
1,686
178
106
The difference will always be divisible by 9. And any number divisible by 9 has digits that sum up to 9.
 

KarenMarie

Elite Member
Sep 20, 2003
14,372
6
81
Originally posted by: Transition
Doesn't work if you use a number like 5566

yea... i picked 1122 the second time and it got it wrong.

Still got it right the first time.