There are still a lot of people who grind their brains every day while solving a sudoku. But did you know that these days that is a bit for wimps? If you want to torture your brain even more seriously, you can visit the Calk document. In a playing field of AxA cells, each row and column must contain the number 1 to A. In addition, areas are indicated in which you must use those numbers to produce a given number by adding, subtracting, dividing or multiplying. On the Calkdocu site you will find daily new puzzles in different levels of difficulty ranging from simple to inhumane.
Play Calcdoku here.
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Calcdoku – A kind of sudoku but for advanced users
