# Lesson 13

Multiplying, Dividing, and Estimating with Scientific Notation

Let’s multiply and divide with scientific notation to answer questions about animals, careers, and planets.

### Problem 1

Evaluate each expression. Use scientific notation to express your answer.

- \((1.5 \times 10^2) (5 \times 10^{10})\)
- \(\dfrac{4.8 \times 10^{\text-8}}{3 \times 10^{\text-3}}\)
- \((5 \times 10^8) (4 \times 10^3)\)
- \((7.2 \times 10^3) \div (1.2 \times 10^5)\)

### Problem 2

How many bucketloads would it take to bucket out the world’s oceans? Write your answer in scientific notation.

Some useful information:

- The world’s oceans hold roughly \(1.4 \times 10^{9}\) cubic kilometers of water.
- A typical bucket holds roughly 20,000 cubic centimeters of water.
- There are \(10^{15}\) cubic centimeters in a cubic kilometer.

### Problem 3

The graph represents the closing price per share of stock for a company each day for 28 days.

- What variable is represented on the horizontal axis?
- In the first week,

was the stock price generally increasing

or decreasing? - During which period did the closing price of the stock decrease for at least 3 days in a row?

### Problem 4

Write an equation for the line that passes through \((\text- 8.5, 11)\) and \((5, \text- 2.5)\).

### Problem 5

The point \((\text-3, 6)\) is on a line with a slope of 4.

- Find two more points on the line.
- Write an equation for the line.

### Problem 6

Explain why triangle \(ABC\) is similar to triangle \(CFE\).

### Problem 7

Two students join a puzzle solving club and get faster at finishing the puzzles as they get more practice. Student A improves their times faster than Student B.

- Match the students to the Lines \(\ell\) and \(m\).
- Which student was faster at puzzle solving before practice?