Across the Country 18, 19, 20 — Martha E.H. Rustad

Six new books in this colorful series introduce beginning math concepts. Count by 2s, 5s, 10s, and even all the way up to 100! Each book increases number familiarity, counting, and math skills, while also introducing fun facts about popular early childhood topics. Count up to 20 by ones, learning about vehicles ranging from motorcycles and school buses to hot air balloons.