Calculate and solve problems with scientific notation

Answer Key - Grade 8 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Bo reads that light travels about 3 × 10^5 km each second. How far does it travel in 6 × 10^1 seconds, in scientific notation?

   1.8 × 10^7
2. 2.

   Esme reads that a heart beats about 1.2 × 10^5 times a day. How many beats is that in 3.65 × 10^2 days, in scientific notation?

   4.38 × 10^7
3. 3.

   Jun reads that about 8 × 10^9 people each take about 2.5 × 10^2 breaths in 15 minutes. How many breaths is that in all, in scientific notation?

   2 × 10^12
4. 4.

   Kira reads that the oceans hold about 1.4 × 10^21 liters of water and that 8 × 10^9 people live on Earth. How many liters is that per person, in scientific notation?

   1.75 × 10^11
5. 5.

   Our galaxy has about 2 × 10^11 stars. Luz imagines sharing them among 4 × 10^3 classes. How many stars would each class get, in scientific notation?

   5 × 10^7
6. 6.

   In Milo's notes, a dust speck is 6 × 10^-5 m across and a virus 8 × 10^-8 m. How many viruses fit across the speck, in scientific notation?

   7.5 × 10^2
7. 7.

   A city library has 6.4 × 10^6 pages of old newspapers. Noah scans 3 × 10^5 of them. How much is left, in scientific notation?

   6.1 × 10^6
8. 8.

   Pia reads that a forest has 5.2 × 10^7 trees, and 8 × 10^5 fall in a storm. How much is left, in scientific notation?

   5.12 × 10^7
9. 9.

   Zee's bike ride is 7 × 10^3 m long. Which length is the same, in a better-sized unit?

   • 70 km
   • 7 km
   • 7 mm
   • 7 cm
10. 10.

    Ari reads that a leaf is 2.3 × 10^-2 m wide. Which width is the same, in a better-sized unit?

    • 2.3 km
    • 23 cm
    • 2.3 cm
    • 2.3 m