In this clip the teacher is leading a discussion about what the graph of the situation will look like.
The Box Problem, Clip 2, 3:44
A group suggests the formula which has not been done as a class. In order to allow time for the other students to discuss this formula, the teacher has them discuss the formula in their groups.
It is possible that some students in the class may find the formula before that section of the activity is reached, this is one away of handling it so the other students can catch up.
Notice how the instructor goes around and monitors groups' progress.
The teacher also summarizes with the class at the end. She makes use of one of the boxes the students have created.That will help give value to the students' boxes
