Calcudoku / Mathdoku is a fun Sudoku variant that will help your math and logic. Complete the grid such that every row and column contains the digits 1 to the size of the grid. Each row and column contains each digit only once. A cage clue tells you the answer after the cage values have undergone the specified mathematical operation. The clue doesn't tell you which way around the digits occur, just the answer to the calculation. A digit can appear more than once in a cage.