Ok, this is fairly simple game but its addictive. I like soduku better though. The basic rules are the same. For a X*X board, use 1 - X numbers to fill each row and each column. No number in a row and a column can be repeated.

Further, there will be boxes called cages. The numbers inside a cage should equate to the number given in left upper corner of that cage. The operation that should be done on the numbers is also given. So if a cage has 5+ written in it. It means the numbers in the cage have to be added up to make 5.