# Lesson 9

Describing Large and Small Numbers Using Powers of 10

### Lesson Narrative

This lesson serves as a prelude to scientific notation and builds on work students have done in previous grades with numbers in base ten. Students use base-ten diagrams to represent different powers of 10 and review how multiplying and dividing by 10 affect the decimal representation of numbers. They use their understanding of base-ten structure as they express very large and very small numbers using exponents.

Students also practice communicating—describing and writing—very large and small numbers in an activity, which requires attending to precision (MP6). This leads to a discussion about how powers of 10 can be used to more easily communicate such numbers.

### Learning Goals

Teacher Facing

• Describe (orally and in writing) large and small numbers as multiples of powers of 10.
• Interpret a diagram for base-ten units, and explain (orally) how the small squares, long rectangles, and large squares relate to each other.

### Student Facing

Let’s find out how to use powers of 10 to write large or small numbers.

### Required Preparation

Print and cut up cards from the included blackline master.  Prepare 1 set of cards for every 2 students.

### Student Facing

• Given a very large or small number, I can write an expression equal to it using a power of 10.

Building On