Calcudoku Puzzle Magazine
Calcudoku is a variant on killer sudoku. Rather than simply having caged regions (those that have a thick border) that must sum to a certain value, there are three other possibilities to contend with too.
The first of those possibilities is multiplication. This works in the same way as addition does, because it doesn't matter what order you perform the calculation in. Just like 2 + 4 + 5 = 11 and 5 + 2 + 4 = 11, so 2 x 3 x 4 = 24 and so does 3 x 2 x 4.
However, the other two new options are division and subtraction, which work a little differently. With subtraction you always take the lower numbers away from the highest number in a region. For instance, if there are 3 cells and a total of "1-", then in a 6x6 puzzle one option for this region would be 6 - 4 - 1. Note that the actual values in each cell could be any of these, for instance if the cells were in a horizontal region, then reading left to right the values could be 1, 4, 6: as the solver you just need to remember to always subtract the smaller values from the highest value.
With division, the process works exactly as above: you divide the highest number by the lower numbers. And that is all there is to it! At first calcudoku can seem a bit daunting. That's way the calcudoku puzzle magazine starts with easier puzzles, and as you move through the magazine the puzzles get progressively harder. Thus puzzles 1 - 4 as shown on the sample page below are fairly gently to ease you into things. And of course you can use the usual sudoku rules to help solve calcudoku, just remember there are no box regions, and also - crucially - that you are allowed to repeat numbers within sum regions (subject to the usual constraint that each row and column must contain 1 - 6 just once of course).
You can take a look at a calcudoku magazine page. The magazine contains 50 pages, 25 of puzzles with 4 puzzles per page, with difficulty increasing through the title, and 25 pages of solutions. Print the puzzles off whenever you want them, whether you choose to print a page at a time to do on the daily commute or prefer to print all at once is entirely up to you. You may choose not to print the solutions but rather check them on the screen.
To download the Calcudoku Puzzle Magazine in PDF format on A4 paper to print off the puzzles you want when you want to play them, all for just £1.97 (UK Pounds) or $3.15 (US Dollars) - click the 'Buy Now' button below: