Killer Suduko

Killer Suduko is an alternative version of the game of Suduko.

Exactly like Suduko, to solve the puzzle each row, column and 3x3 grid must contain the numbers 1 to 9 once. However unlike Suduko there are no "givens" in the initial puzzle. Instead areas of the grid are "caged" and each "cage" has a number. This number is the sum of all the solutions in that "cage".