Application Development for iPhone, iPad, and iPod touch
Killer Sudoku follows the rules of standard Sudoku i.e. every row, column and block (3 x 3 cell area) must contain all the numbers 1 to 9 with no duplicate values. Whereas standard Sudoku starts off with some of the cell values filled in, Killer Sudoku initially has all cells blank. Instead cells are grouped together into "cages" and the sum of these is given. There is an additional rule that no number within a cage can be duplicated.