Sudoku Book with 120 Puzzles.
Includes 3 challenge levels; easy, medium & hard. Each level has its own index with hyperlinks for quick navigation to each of the 40 puzzles and answer keys for each level.
Designed to be opened and utilized on your iPad and/or phone with an pdf annotation app like Goodnotes 5 or Noteshelf.
On the solution page are hyperlinks to go back to the original puzzle or go to the next one.