Classic Sudoku - 9x9 Puzzles app for iPhone and iPad

"Looking to relax? Or do you want to give your brain a much needed logical workout? Whatever the case Sudoku is for you! Don’t have a pen? Don’t have any physical Sudokus? Now you can play Sudoku FREE anywhere you’d like.

Choose from 5 levels of difficulty, ranging from ones that feel like a quick walk in the park all the way to difficult mental marathons that will give your brain a real run for its money. With hints, note taking, auto checking and duplicate highlighting, you can either complete the challenge without any help, as you would with a pencil and a piece of paper, or use all the help you’d like."