Sudoku Puzzle Pack - Volume 1 - Version 1.0 This package contains 25 different Sudoku puzzles in varying difficulties from very easy to very hard. The Puzzles are in PDF file format so one can easily print and then work them out with pencil and paper. The package is very small in size and has not to be installed. The rules for solving a Sudoku are simple: Each row, column and region must contain the numerals from 1 through 9 exactly once.