Sudoku Free

**$$$$$$$$ All coins in app are FREE $$$$$$$$** **All levels are FREE** Sudoku Free is really simple sudoku. It is easy to learn but a challenge to master, puzzling players all over world. Test your powers of observation and memory. Fill it as fast as you can, challenge it！ Features, ***4 difficulty models; ***Smart hints; ***Error checking automatically; ***Share it with your friends.