This instructional module investigates the fundamental conceptual frameworks required for students to master addition and subtraction operations at the second-grade level. The authors, Karen Economopoulos and Susan Jo Russell, utilize the pedagogical principles of the Investigations in Number, Data, and Space curriculum to guide educators in fostering mathematical fluency. The text provides a structured approach to developing number sense through inquiry-based learning and the application of concrete mathematical models.

Educators frequently identify this curriculum as a foundational resource for building deep conceptual understanding rather than rote memorization. Experts highlight the text for its emphasis on student-centered discourse and the integration of diverse problem-solving strategies within the classroom environment.