Reasoning-and-Proving in Geometry Textbooks: What Is Being Proved?

As calls are made for reasoning-and-proving to permeate school mathematics, several textbook analyses have been conducted to identify reasoning-and-proving opportunities outside of high school geometry. This study looked within geometry, examining six geometry textbooks and characterizing not only the justifications given and the reasoning-and-proving activities expected of students but also the nature of the mathematical statements around which reasoning-and-proving takes place. The majority of reasoning-and-proving exercises focused on particular mathematical statements, whereas the majority of expository mathematical statements were general in nature. Although reasoning-and-proving opportunities were numerous, it remained rare for reasoning-and-proving to be made an explicit object of reflection. [For the complete proceedings, see ED585874.]