LeapFrog didj Sonic the Hedgehog Super Set Gaming System and Game Bundle Customize. Download. Make it your own game! Study Skills for School! Spelling, Addition, Subtraction, Multiplication, Division, Fractions, Language, Arts, and More! Just the Right Challenge! Skill levels adjust dynamically, and more than 300 tutorials offer help when you need it. Includes: Didj Handheld System, Sonic the Hedgehog Game, & Two Skins. Designed for ages 6-10 years.