Technological pedagogical content knowledge (TPACK) proposes a theoretical framework that incorporates four central components: an overarching conception of what it means to teach with technology, knowledge of students' thinking and understandings of specific topics with technologies, knowledge of curricular materials that incorporate technologies, and knowledge of instructional strategies and representations for teaching subject matter with technologies. This interpretive case study, conducted over a 3-year period, identified descriptors aligned with the four central components of TPACK to highlight differences in teachers' knowledge levels when integrating spreadsheets as learning tools in mathematics. (Contains 1 table and 1 figure.)