This book is aligned with the Common Core State Standards for kindergarten and first grade in mathematics in operations and algebraic thinking (K.OA and 1.OA). 10 monsters, looking fine, 1 folds down. Still up? 9! Photographs of toy dinosaurs, monsters, piglets, and other objects; rhyming text; and a game help children learn that subtraction is a take-away action! Rows of colorful rubber duckies show subtraction facts. Hummingbirds and chickadees show the difference between addition and subtraction in this entertaining introduction to mathmatics.