140 pages of fun! Journey under the sea with Buster and Lass for a skip counting adventure by 2s and 3s! It's fun and different. Perfect for ages 6 months to 6 years.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. In this Big Book edition, we've included the story in full and standard editions, fun extras that allow children to meet the critters and explore Bugville, and 40 flash cards for skip counting by 2s and 3s.