Zone 21 – Math Solitaire is possible preorder on Apple Appstore now. This is really fun card game to everyone who likes quick gameplay and fast thinking. It’s amazing how fast you evolve on this game. What’s the goal? The goal is really simple, try to keep foundation value near to 21, if you get 21 you hit the zone and get bonus score. Foundation value can’t go under zero or over 21. First you keep value between these values, but soon you are able to hit the zone very often.