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, and 9 Irregular regions contains each number exactly once.The sum of all numbers in a cage must match the small number printed in its corner.No number appears more than once in a cage. (This is the standard rule for killer sudokus, and implies that no cage can include more than 9 cells.)Center Dot is a variant of sudoku, where central cells of each region form an extra region. This region must contain digits 1 through 9.