# Algebraic Expressions Lesson 3 Episode 4 (Teachers)

### Exploring

No captions Captions
Stop the video above first if it is playing.

Haleemah and ET generalize new methods for finding the total amount spent by the friends on game apps. They write an equation that shows the relationship between the cost per app and the total amount spent by the friends.

### Episode Supports

Focus Questions

For use in a classroom, pause the video and ask these questions:

1. [Pause the video at 2:20] Haleemah and ET have created a more efficient equation that relates the cost of each app to the total amount spent by the three friends. Ask your students why they think the new expression 9c represents the total amount spent by the three friends.
2. [Pause the video at 6:41] ET and Haleemah have written two equations: 9c = T and (3 + 2 + 4)c = T. Before hearing ET and Haleemah’s thoughts on how the two equations are alike and different, pose that question to your students. As you restart the video, encourage them to notice how their answers compare to ET and Haleemah’s.

Supporting Dialogue

1. After trying their new equation 9c = T with c = \$4, ET and Haleemah get a total cost of \$36. Haleemah claims this makes sense because when they tried a cost per app of \$2 with their old equation, 3c + 2c + 4c = T, they got a total cost of \$18 [2:38]. Ask your students to make sense of Haleemah’s claim—why might that help convince Haleemah that their new equation is correct?
2. After watching the video, ask your students to talk with a partner about the three equations they’ve seen so far (you may want to display these somewhere): 3c + 2c + 4c = T; 9c = T; and (3 + 2 + 4)c = T. Ask them to consider which one they would prefer to use and justify their choice. Ask them if they think the equations are the same, and if so, how do they know.