The goal of a Calcdoku puzzle is to fill the squares with a single digit each, with the following rules:
Each of the digits through is used exactly once in each row and column. (There is no region rule as in Sudoku.)
Any marked region indicates a number and an operation or The operation applies to digits in the region, and when applied to the digits in some order, they result in the given number. In the example below, the region marked must be filled with three digits selected from through that have a sum of Digits can be repeated in a marked region, but not in a row or column.
Keep reading to see two example puzzles, or jump straight to the daily challenge below.