Eliminate memory-overload and learn 4 math facts on each side of a card! Triangle Flash Cards teach families of facts, showing the inverse relationship between multiplication and division. How is 3 in one corner related to 9 and 27 in the other corners? Cover the product in blue, and practice multiplication. Cover one of the factors in black, and practice division. A total of 20 cards aid in mastery of 80 math facts, including factors and divisors from 1 through 9. For 2 or more players, grades 1+.