MysticalBall.com

Check the game at,

http://www.mysticalball.com/

How does it work?

1. Guess any two digit number
  
   Say,
      xy (where x and y can be from 0,1,2…9)
   So, number will be
      (10x + y)   ………(i)

2. Add two digits and subtract total from the original number
  
   Add two digits,
      (x + y)
   Subtract total from the original number
      (10x + y) - (x + y)
      = 9x
  
  
   So, considering x values 0,1,2….9
   solution can be any number of,
      0, 9, 18….81
     
In symbols, above numbers have same symbol, which comes in the ball!

- Hardik Tank