Emily and Mauricio create a drawing of a square of fabric that is some unknown number of inches long on each side. They select variables to represent the length, width and area of the fabric.
Episode Supports
Students’ Conceptual Challenges
As in Episode 7 of the previous lesson, Mauricio and Emily use several variables when one would suffice [3:21]. Their use of these variables (x for the area of the square, L for the length, and W for the width) seems productive for them as they make sense of this task. Using fewer variables requires recognizing and using relationships between quantities in the context, which is an important and powerful mathematical skill. The use of fewer variables can also help with (and is sometimes required for) solving some problems. Thus, try to encourage your students to recognize and use relationships, as the instructor does in the next episode with Emily and Mauricio.
Focus Questions
For use in a classroom, pause the video and ask this question:
[Pause the video at 2:14] How would you draw Zara’s fabric? Be sure to label the length, width, and area.
Supporting Dialogue
[Pause the video at 2:14] Emily says she doesn’t understand what the task is asking. What sense do you make of this task? What would you say to Emily to help her understand what she is supposed to do?
