Facilitating discussion in math class is a particularly powerful teaching method. It challenges students to put their solution strategy into words. It promotes communication between students. It also highlights any unclear steps that may have been glossed over otherwise.
Teachers in the Innovations Project have been making use of the Contexts for Learning Investigations, a series of mini-lessons, games, and storybooks based around overarching math learning goals. The developers of this series argue that math time should be an active and creative process, allowing students to learn through experimentation and exploration.