Teach and review subtraction facts individually, in groups, or with the whole class! Each flash card set contains a collection of full-color, high-interest student cards as well as instructions and tips for the teacher or parent, suggested activities, and additional blank cards. Each card has a hole in the top corner that can be fit with a ring or string to help with organization and storage. Additionally, each card has one corner that is shaped differently than the others. By lining up the non-rounded corners, the flash cards can quickly be faced in the same direction. When applicable, flash card sets include answers in small print on the reverse side of each card. Each card measures 3-1/8" x 5-1/8". 170 double-sided cards per pack.