Hot Dots Math Flash Cards - More Subtraction, Use as basic flash cards or add the Hot Dots pen for instant reinforcement- - just touch the pen to the correct answer to get a positive response, Set includes 50 double-sided cards for 100 interactive math problems, Ages 6+/Grades 1+, Dimensions:, Length: 5, 7, Height: 2, 2, Width: 3, 9 SKU: EDCI087