Play Killer Sudoku or Sumdoku. Fill the grid with numbers 1 through 9, so that each row, column, and box contains each number only once. In addition, a Killer Sudoku grid is divided into cages, each with its own background color. The values of the cells in the cage must sum to the sum of the values of that cage, shown in the top left corner of the cage. The same number cannot appear in a cage more than once.