Updated on May 1, 2018
★ 5 crazy difficulties ( beginner, easy, medium, hard, and insane) with 500 lessons respectively
★ Highlight row, cell, number, errors and so on
★ Notes
★ Save the shortest time of player, sort player rankings
★ Smartphones and tablets support
★ Play & share this puzzle game with friends
★ Play free and offline
★ Friendly interface, easy to play