Algebra is a foundational concept in the study of mathematics, and readers will delight in learning the principles of operations and algebraic thinking in a relatable and engaging way. Topics such as adding and subtracting within 20, using algebraic principles to solve equations and word problems, and understanding the relationship between addition and subtraction will give beginning math students a firm grasp on basic math concepts. This volume, written to the Common Core State Standards for Mathematics, follows Diego as he adds starfish and beach balls to solve addition word problems at the beach. This volume meets CCSS Math Standard 1.OA.A.1. This book should be paired with "A Day at the Beach" (9781477720196) from the Rosen Math Readers Program to provide the alternative point of view on the same topic.