Whole-class discussions are an essential feature of the Investigations curriculum. Discussions provide students the opportunity to articulate, represent, connect, and consolidate mathematical ideas.
The curriculum supports teachers in facilitating discussions by recommending strategies to look for, specifying key mathematical ideas to focus on, and offering examples of student ideas and dialogue.
See examples of the above in the discussion in Grade 2, Unit 6, Session 1.1 (pdf). The discussion begins on page 27, but suggestions to the teacher about planning for it begin on the bottom of page 26. Also, read an example of that discussion in one classroom: Dialogue Box: Adding With Stickers (pdf).