Through an analysis of instruction in mathematics classrooms at a community college, the author describes the nature of the interaction and the complexity of the mathematical activities evident in two types of courses: remedial and science, technology, engineering, and mathematics (STEM) college preparatory courses. Although both types of courses exhibited high levels of student participation, students in remedial courses had more opportunities to participate than students in the STEM courses. However, the complexity of the activities in both courses centered on basic cognitive processes using mostly factual and procedural knowledge. This type of instruction is at odds with reform calls advocating student-centered instruction focusing on complex mathematical thinking. The author's findings suggest avenues for further research and some implications for faculty development. (Contains 6 tables, 1 figure, and 1 footnote.)