I examined how 8 experienced secondary mathematics teachers used interactive whiteboards (IWBs) to elicit student thinking. The study design used a two-phase process: (1) prequalification of participants based on experiences levels involving IWBs and student-centered instruction and (2) multiple data collection cycles of observations followed by video-stimulated recall interviews. Classroom observations involved whole-class discussion in which teachers engaged students in an exploration of mathematics that attended to problem solving, multiple representations, and connections. I analyzed the data using two frameworks that allowed me to examine teaching practices specific to mathematics instruction. The first framework, emergent perspective (Cobb & Yackel, 1996), promotes teaching mathematics as a sociocultural process. The second framework, Technological Pedagogical and Content Knowledge (TPACK, Mishra & Koehler, 2006), delineates the combinations of teacher knowledge domains (technological, pedagogical, and mathematics content) that are enacted in technologically rich environments. I developed a classification scheme for the way teachers used IWBs to support their instruction: (a) digital accentuation, (b) digital proximity, and (c) digitally enabled exploration. When using the IWB for digital accentuation the teachers used colored pens and highlighters to draw attention to particular features of graphs, equations, or diagrams. Digital proximity consisted of two processes-- “bringing or keeping elements on the screen together and deliberately separating elements on the screen. Teachers used the IWB features of extending pages or shrinking existing material to create space for new material or to keep related content in close proximity. They created new pages, hid content behind covers, and used the undo feature to visually separate content that they saw as unrelated or not germane to the task at hand. Students rarely used these IWB features. Teachers used a variety of IWB features to experiment with mathematical ideas. Although the suggestions for experimentation came from students, the teacher was generally in control of the IWB. Teachers' use of the IWB classified as digitally enabled exploration reflects the coincidence of all three TPACK domains. I propose that if a teacher's instructional goal is to enact IWB-based lessons involving student-centered problem solving, that instruction needs to reflect the concurrence of all three TPACK knowledge domains.