To improve understanding of identities and inverses, and to provide a stronger foundation for future mathematics, Sandra Miles designed a two-part lesson that makes the relationship between identities and inverses explicit. This article illustrates Miles' teaching of the first part of the lesson, focused on addition and subtraction, and then gives key ideas for how to extend the concepts to multiplication and division. Miles' goal for the first portion of this lesson was to help students use what they know about addition to understand the concepts of identity and inverse. This lesson was implemented with eight students from sixth and seventh grade. This is an ideal age to help students explicitly learn about the identity and inverse because they already have a conceptual understanding of the elementary operations and are familiar with the use of symbolic representations. The materials used for this lesson include a short PowerPoint® presentation (link online) that introduced the students to acids and bases and a student activity sheet (link online).