121 puzzles for the advanced solver: twin puzzles, extra large puzzles (up to 17×17!), with exponentiation, modulo, without operators, etc. Score 12 points on the site for each correct solution.
100 free puzzles: ideal to get started with Calcudoku's. One hundred puzzles from 3×3 to 9×9, ranging from very easy to quite difficult.
|250 (!) Killer Sudoku puzzles, from easy to difficult. For each of the 75 difficult puzzles you can score 9 points on the site.|
|As paperback:|| Amazon US|
| Amazon US|
|As PDF download:||lulu.com|