The purpose of this case study is to highlight the integral role that progress monitoring (PM) plays throughout any response to intervention (RTI) process. This example uses a three-level, responsiveness-to-intervention (RTI) method for identifying students with learning difficulties. Using a fictional third-grade classroom as the setting for this example, readers are provided with a framework of the RTI identification process, along with frequent opportunities to test their comprehension of the information presented. First, an overview of RTI and PM is provided, followed by an introduction to Mr. Thompson and his third-grade students. The remainder of the case study illustrates the use of RTI as a method for identifying students with learning difficulties, specifically in the area of mathematics concepts/applications. Throughout the text, readers are queried to test their comprehension of material covered, with answers provided for evaluative purposes. Tabular data on the following are appended: (1) Math Risk with Fall CBM [curriculum-based measurement] Screening; (2) Inadequate Math Slopes--Primary Prevention; (3) Quantifying Response to Secondary Prevention in Math; (4) Typical End-of-Year Benchmarks in Math; (5) CBM Math Norms for Student Growth (Slope); and (6) Quantifying Response to Tertiary Prevention in Math. (Contains 1 footnote.)