It’s not a crossword. It’s not some extreme version of tic-tac-toe. So what is KENKEN and where did it come from? Simply put, it’s a grid-based numerical puzzle that uses the basic math operations—addition, subtraction, multiplication, and division—while also challenging your logic and problem-solving skills. By altering the size of a KENKEN grid, from 3 x 3 up to 9 x 9, and employing different combinations of the math operations, five different difficulty levels can be generated, and a seemingly endless number of puzzles. (And many players seem determined to try them all!) In a way, KENKEN is like a game of pool or even chess: The more you think ahead to your next move and consider all the possible outcomes, the better you’ll get—and the smarter you’ll become!