Skip Counting! Our selection of activities and problems provides a fun and easy approach to building skills. This book contains 9 different sets of number flash cards:Counting by 2sCounting by 3sCounting by 4sCounting by 5sCounting by 6sCounting by 7sCounting by 8sCounting by 9sCounting by 10sRepetition is the key to success. Initially, focus on one number set at a time. Look for these related books:Undersea, 2, 3 with Buster and FriendsUndersea, 4, 5 with Buster and FriendsUndersea, 6, 7 with Buster and Friends