Master math skills! This set of Subtraction flashcards includes 3 decks of cards (162 cards); the front of the card shows the addition problem, while the back of the card reveals the answer. Each flash card pack has its own color-coded edges. Deck 1 has green edged cards and includes the subtraction families 1 to 10. Deck 2 has blue edged cards and includes the subtraction families 1 to 20, and Deck 3 has red edged cards and includes subtraction families 1 to 100. Ages 5 and Up.