Killer Sudoku Girandola - 500 Sudoku Puzzle
The objective is to fill the grid with numbers from 1 to 9 in a way that the following conditions are met:
- Each row, column, 3x3 box and the nine gray cells contains each number exactly once.
- The sum of all numbers in a cage (grouping of cells denoted by a dotted line) must match the small number printed in its corner.
- No number appears more than once in a cage.
Nr. 1 - 100 = easy
Nr. 101 - 200 = medium
Nr. 201 - 500 = hard