Teachers' 1st choice for over 25 Years. Durable, thick card stock. Sturdy boxes. Notched corners for quick sorting. Great for teaching the relationship between +/- and x/÷, (e.g.: 3+1=4 on one side, 4-1=3 on the reverse). Set of 90 classroom-sized cards. Measure 6 1/2" x 3 1/4" (16cm x 8cm).

Multiplication/Division Cards: These double-value flash cards in vertical format consist of 81 cards printed two sides, one side printed with a multiplication problem and the other side with a directly related division problem (e.g. 3x1=3 on one side, 3÷3=1 on the reverse).

Addition/Subtraction Cards: These double-value flash cards in vertical format consist of 81 cards printed two sides, one side printed with an addition problem and the other side with a directly related subtraction problem (e.g. 3+1=4 on one side, 4-1=3 on the reverse).