Features: Easy to Use:Rotate the gear in one second to change the question and it is easy to use and the question is easy to rotate.The upper gear changes the number in this area and rotate the lower gear to change the number in this area. Massive Questions: Slide the paddle to switch operation symbols double the number of questions/operation symbols freely choose nearly 10 000 permutations and combinations. Eco-Friendly: Paperless answering questions saving paper and protecting the forest parental counseling artifact interesting teaching let children fall in love with mathematics. Excellent Effects: Practice once a day for three weeks to improve the child's verbal and mental arithmetic ability; answer the test faster and save answering time. Perfect Gift: It's a great gift for kids friends or family. It's compact and portable. Fun teaching tool let kids children fall in love with mathematics. Specifications: Material: Plastic Product Size: 13.2*4.4cm includes: 1 *Arithmetic Tablet