Twenty One Minus Flash Cards - All of our flash cards are double sided. Two sided subtraction flash cards are made by folding the print out twice (quarterfold) so that the problem is visible on one side of the card and the solution is visible on the opposite side of the card. The numbers are printed in gray to reduce one's ability to see through the card and read the answer on the opposite side.
This set includes four cards. Select an item below to print your flash cards for the problems 21 minus 9 equals 12 through 21 minus 12 equals 9.
