Understanding the principles of base ten is essential to understanding numbers and operations. Students will build upon their knowledge of place value and be challenged to use it in the context of algebraic operations. Engaging content encourages students to demonstrate the knowledge they’ve gained from reading. Eye-catching visuals help walk readers through the math problems, while age-appropriate language encourages learning. Readers join Savannah as she goes snorkeling and identifies fish, learning how to use place value to round whole numbers. This volume meets CCSS Math Standard 3.NBT.A.1.