Carson Dellosa's Addition & Subtraction Flash Cards present an easy fun way kids to practice essential skills. This flash card set includes 54 flash cards, half addition problems, half subtraction, each represented by different color cards easy recognition of type of problem your child is solving. Set includes instructions for card game war, as well as other games that can be played with set. Includes an answer key card. Each card has rounded corners fast easy flipping. Flash cards allow kids to develop critical thinking, decision-making, turn-taking, other skills while allowing them to learn a fun, hands-on way.