# Lesson 9

Describing Large and Small Numbers Using Powers of 10

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

### Problem 1

Match each number to its name.

1. 1,000,000
2. 0.01
3. 1,000,000,000
4. 0.000001
5. 0.001
6. 10,000
• One hundredth
• One thousandth
• One millionth
• Ten thousand
• One million
• One billion

### Problem 2

Write each expression as a multiple of a power of 10:

1. 42,300
2. 2,000
3. 9,200,000
4. Four thousand
5. 80 million
6. 32 billion

### Problem 3

Each statement contains a quantity. Rewrite each quantity using a power of 10.

1. There are about 37 trillion cells in an average human body.
2. The Milky Way contains about 300 billion stars.
3. A sharp knife is 23 millionths of a meter thick at its tip.
4. The wall of a certain cell in the human body is 4 nanometers thick. (A nanometer is one billionth of a meter.)

### Problem 4

A fully inflated basketball has a radius of 12 cm. Your basketball is only inflated halfway. How many more cubic centimeters of air does your ball need to fully inflate? Express your answer in terms of $$\pi$$. Then estimate how many cubic centimeters this is by using 3.14 to approximate $$\pi$$.

(From Unit 6, Lesson 24.)

### Problem 5

Solve each of these equations. Explain or show your reasoning.

$$2(3-2c) = 30$$

$$3x-2=7-6x$$

$$31=5(b-2)$$

(From Unit 4, Lesson 13.)

### Problem 6

Graph the line going through $$(\text-6,1)$$ with a slope of $$\frac {\text{-}2}{3}$$ and write its equation.

(From Unit 5, Lesson 9.)

### Problem 7

On a map of Chicago, 1 cm represents 100 m. Select all statements that express the same scale.

A:

5 cm on the map represents 50 m in Chicago.

B:

1 mm on the map represents 10 m in Chicago.

C:

1 km in Chicago is represented by 10 cm the map.

D:

100 cm in Chicago is represented by 1 m on the map.

(From Unit 2, Lesson 5.)