PBS Publishing-Creative Teaching Materials Flash Cards. Answers to each of the equations are shown in small type on the reverse side of the cards to ensure correct answers and help with quick memorization. Work alone or with a partner. Race against the clock and see how many facts you can answer in 1 minute. This package contains fifty 5x3-1/2 inch double-sided flash cards. Recommended for ages 7 and up. Comes in a variety of themes. Each sold separately. Imported.