Children master addition facts through 12…with handy, double-sided flash cards that provide learning fun for everyone! The cards have a different addition problem on both sides—with the answer to each problem in the corner on its opposite side. The set includes 56 durable cards—52 flash cards, 2 activity cards and 2 equation challenge cards—each with quick-sorting, rounded corners. Cards measure 3 1/8" x 5 1/4".