The rules are as follows:
1. The numbers you can use are from 1 to 6 or from 1 to 9.
2. In each row and in each column each number can appear only once (just like in Sudoku).
3. Each "cage" (the blocks with the thick border) shows a result and an operation (addition: +, subtraction: -, multiplication: x, or division: /). The operation applied to the numbers in the cage should produce the result shown.
4. A number may be used more than once in the same cage, but not more than once in each row or column.
In case of subtraction or division, arrange the numbers from the cage from largest to smallest. If the outcome = 1- and the numbers in the cage are 1, 2, 4 then you need to arrange them into 4 - 2 - 1.
To create your printable calcudoku puzzle is extremely easy. First you slected the gridsize (6x6 or 9x9). Then select how many fields in the puzzle should be printed with the number. Finally you click on download the calcudoku puzzle. It will create a pdf file for you. This pdf file contains 2 pages, one page is the puzzle and the second page contains the answer sheet.
Every calcudoku puzzle is dynamically created. Therefor every puzzle is unique and you can download as many puzzle as you need.