Explore some general strategies for successfully solving simple games and puzzles. As you hone your skills at games and puzzles, including 20 Questions, Mastermind, Ghost, The Tower of Hanoi, variations of Tic Tac Toe, and Cram (a cross between checkers and dominoes), you’ll start seeing how mathematical ideas and concepts—including the strategy of working backward and the exploitation of symmetry—are essential to increasing your chances of winning.