7th Grade Scientific Notation: Subtraction & Multiplication Challenges

A scientist measures the mass of a small particle as 3.5 x 10^-27 kg. If another particle has a mass of 1.2 x 10^-27 kg, what is the difference in their masses in scientific notation?

• 1.5 x 10^-27 kg

• 3.0 x 10^-27 kg

• 2.3 x 10^-27 kg

• 4.7 x 10^-27 kg

A cell in a petri dish contains 2.5 x 10^6 bacteria. After a day, the number of bacteria doubles. How many bacteria are there now, expressed in scientific notation?

• 1.0 x 10^7

• 5.0 x 10^5

• 2.0 x 10^6

• 5.0 x 10^6

The distance from Earth to a nearby star is approximately 4.2 x 10^16 meters. If a spacecraft travels 1.5 x 10^16 meters towards the star, how far is it from the star now in scientific notation?

• 4.0 x 10^16 meters

• 1.2 x 10^16 meters

• 3.5 x 10^16 meters

• 2.7 x 10^16 meters

A comet is traveling at a speed of 2.3 x 10^4 km/h. If it travels for 3.5 hours, how far does it travel in scientific notation?

• 9.1 x 10^4 km

• 6.3 x 10^4 km

• 7.5 x 10^4 km

• 8.05 x 10^4 km

A researcher finds that a certain chemical is present in a solution at a concentration of 5.0 x 10^-3 mol/L. If 2.0 x 10^-3 mol/L is removed, what is the new concentration in scientific notation?

• 5.0 x 10^-3 mol/L

• 2.0 x 10^-3 mol/L

• 3.0 x 10^-3 mol/L

• 4.0 x 10^-3 mol/L

The height of a mountain is approximately 8.8 x 10^3 meters. If a valley is 2.5 x 10^3 meters deep, what is the difference in height between the mountain and the valley in scientific notation?

• 6.3 x 10^3

• 1.13 x 10^4

• 9.0 x 10^3

• 1.0 x 10^4

A computer processes data at a rate of 1.2 x 10^9 bits per second. How much data can it process in 5 seconds, expressed in scientific notation?

• 7.2 x 10^9 bits

• 6.0 x 10^9 bits

• 5.0 x 10^9 bits

• 1.0 x 10^9 bits

A small planet has a diameter of 1.5 x 10^7 meters. If another planet has a diameter of 3.0 x 10^6 meters, what is the ratio of their diameters in scientific notation?

• 2.0 x 10^1

• 1.0 x 10^0

• 4.0 x 10^0

• 5.0 x 10^0

A factory produces 4.5 x 10^5 toys in a month. If production increases by 2.0 x 10^5 toys next month, what will be the new production total in scientific notation?

• 4.0 x 10^5

• 7.0 x 10^5

• 5.5 x 10^5

• 6.5 x 10^5

The volume of a small water bottle is 3.0 x 10^-2 cubic meters. If a larger bottle has a volume of 1.2 x 10^-2 cubic meters, what is the difference in volume between the two bottles in scientific notation?

• 2.1 x 10^-2

• 1.0 x 10^-2

• 1.8 x 10^-2

• 3.0 x 10^-2