The puzzles, either 6 x 6 or 9 x 9, look like Killer Sudoku games, but in addition to numbers, players also contend with math operators (+ - × ÷) within “fences†on the puzzle. Players reach the total at the top left of the fenced area by using the operator on all the numbers within it. Although the solution is a valid Sudoku solution, Kendoku numbers are allowed to be repeated within a fenced area as long as the result doesn't break the rules for a valid Sudoku.