Enter the speedy world of Leapster Sonic the Hedgehog X from Leap frog. Great activity game to encourage children in educational play. Teaches counting, sequencing, addition and subtraction.Help Sonic save his friends from the evil clutches of Dr. Eggman! Jump, run, spin-dash and soar through different zones as you master math skills and collect gold rings to rescue Amy Rose and Knuckles in this fast-paced spinning game.For use with the LeapFrog Leapster 2 Learning System (sold separately).