Multiplying and Dividing with Scientific Notation

The mass of a dust particle is approximately 7.5 x 10 ^-10 kilograms and the mass of an electron is 9.1 x 10 ^-31 kilograms. Approximately how many electrons have the same mass as one dust particle?

• 1.21 x 10²⁰

• 1.21 x 10²¹

• 8.24 x 10²⁰

• 8.24 x 10²¹

The closest distance between Earth and Mars is approximately 3.39 x 10⁷ miles. The fastest rocket leaving Earth travels at an average speed of approximately 3.6 x 10⁴ miles per hour. At that rate, which expression could be used to determine the approximate number of hours it would take the rocket to travel that distance?

• (3.39 x 10⁷) – (3.6 x 10⁴)

• (3.39 x 10⁷) ÷ (3.6 x 10⁴)

• (3.6 x 10⁴) - (3.39 x 10⁷)

• (3.6 x 10⁴) ÷ (3.39 x 10⁷)

City X has a population of 3 x 10⁵ and City Y has a population of 6 x 10⁶. Which statement correctly describes the relationship between the populations of City X and City Y?

• The population of City Y is 2 times the population of City X.

• The population of City Y is 20 times the population of City X.

• The population of City X is 300,000 less than the population of City Y.

• The population of City X is 3,000,000 less than the population of City Y.

Bianca and Nick are both musicians who sell their songs online. During the same year, Bianca sold 8 x 10⁵ downloads of her songs and Nick sold 4 x 10⁶ downloads of his songs. How many times as much is the number of songs that Nick sold than the number of songs that Bianca sold?

• 2

• 5

• 20

• 40

Kevin moved from a city to a small town. The population of the city is 8 x 10⁴ , which is about 20 times as great as the small town. What is the approximate population of the small town?

• 1.6 x 10⁵

• 1.6 x 10⁶

• 4 x 10³

• .4 x 10⁴

There are about 3 x 10¹² trees on our planet. There are about 3 x 10¹¹ trees in the United States. How many times as much is the number of trees on the planet than the number of trees in the U.S.?

• 10

• 5

• 100

• 20

Andrew played 9.6 x 10² hours of video games last year. Fahim played 2.4 x 10² hours of video games last year. How many times as much is the number of hours Andrew played than the number of hours Fahim played?

• 4

• 2

• 3

• 5

Last year, William watched 3.8 x 10² episodes of tv on Netflix. This year, he watched about 1.14 x 10³ episodes of tv on Netflix. How many times as much is the number of shows he watched this year than the number of shows he watched last year?

• 5

• 4

• 3

• 2