This simple and free math game that is similar to Sudoku but requires some arithmetic as well as logic. The objective of the game is to fill the grid in with the digits 1 through 6 such that: 1) Each row contains exactly one of each digit, 2) Each column contains exactly one of each digit 3) Each bold-outlined group of cells is a cage containing digits which achieve the specified result using the specified mathematical operation: addition (+), subtraction (−), multiplication (×), and division (/).