Unit 7, Lesson 4
Dividing Powers of 10
Grade 8
Preparation
Lesson Narrative
In this lesson, students continue to make use of repeated reasoning to discover the exponent rule .
Students begin by examining different ways to write fractions that are equivalent to 1. Next, they expand expressions written as the division of two powers of 10 and notice patterns when asked to write the quotient using a single power of 10 (MP8).
Students extend this rule to see what happens when dividing by a value with an exponent of 0. They notice that the original value remains unchanged, helping students to make sense of why is defined to be equal to 1. Cases in which the exponent is negative will be explored in following lessons.
- Generalize a process for dividing powers of 10, and justify (orally and in writing) that $\frac{10^n}{10^m} = 10^{n−m}$.
- Use exponent rules to multiply and divide with $10^0$, and justify (orally) that $10^0$ is 1.
Let’s explore patterns with exponents when we divide powers of 10.
Required Preparation
Create a visual display (or add to an existing display) of the exponent rule to be displayed for all to see throughout the unit. A sample display can be seen in the Activity Synthesis.