From counting to adding teens, there are many steps to learning addition and subtraction. In this approachable book about addition and subtraction, readers meet Mo who is also learning these concepts. Alongside this cute blue monster, readers cover the basics of addition and subtraction, including greater than and less than, adding multiple numbers at a time, and tackling problems that use large numbers. A great supplement to the elementary math curriculum, this book includes many practice problems as well as an answer key so readers can check their work.