Skip counting fun! Join Buster and Lass and their undersea friends for a special counting adventure. It's a fun and different way to learn number skills. Instead of focusing on simple 1-2-3 skills, this book focuses on number sequencing and grouping by 4s and 5s. The ability to see groups of items and know their count is an essential skill for your child's development and forms the basis of many more advanced number skills.