Exponentials Lesson 6 Episode 4 (Teachers)

Repeating Your Reasoning

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Arobindo and Josh find the time when the beanstalk reaches a height of about 1.24573 cm.

Episode Supports

Students’ Conceptual Challenges

Josh and Arobindo realize that they need to find the fifth root of 3 raised to the power of three, but other students might need more time to make sense of this problem. If that is the case with your students, consider prompting them to draw a timeline and label it with the information they know. Ask them to indicate with a circle or arrow what information they are looking for, and then encourage them to discuss with one another how they might use the tools they have developed to find that information.

Focus Questions

For use in a classroom, pause the video and ask this question:

[Pause the video at 0:34] Jill has measured the height of the beanstalk on Day 1/5 as 1.2457 cm. Decide for yourself the point at which the beanstalk will reach a height of 1.24573. Justify your answer by using a timeline.

Supporting Dialogue

Josh describes the relationship he sees between the height of the beanstalk on Day 1/5, 1.2457 cm, and the height of the beanstalk on Day 2/5 [4:10]. Ask students to restate Josh’s explanation in their own words and to extend that thinking to the task of finding when the plant is 1.2457cm tall.