They identified two broad classes of habits of mind: (a) general habits of mind that cuts across every discipline, and (b) content-specific habits of mind for the discipline of mathematics. General habits of mind include “pattern-sniffing,” experimenting, formulating, “tinkering,” inventing, visualizing, and conjecturing. Mathematical habits of mind, or mathematical approaches to things, include talking big thinking small (e.g., instantiating with examples), talking small thinking big (e.g., generalizing, abstracting), thinking in terms of functions, using multiple points of view, mixing deduction and experiment, and pushing the language (e.g., at first assuming the existence of things we want to exist, such as 20). Habits of mind have two important characteristics: the “thinking” characteristic and the “habituated” characteristic. In addition, habits of mind are reflexively related to classroom practices. Below we discuss various related views of habits of mind. The Thinking Characteristic