420 Sudoku Puzzles for Adults Hard to Extreme

Книга "420 Sudoku Puzzles for Adults Hard to Extreme". You've been playing Sudoku for quite some time so you should think about leveling up next. This book of Sudoku has hard to extreme puzzles. Such puzzles stimulate the brain so that it remains active. The puzzles also encourage your re-focus skills, which is important in accomplishing goals. Grab a copy today.