Powers of ten and scientific notation

Answer Key - Grade 7 Math Worksheet - Building Confidence

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

1. 1.

   10^-2 = 1 ÷ (10 × 10): a 1 on top and 2 tens below the bar. A bee is about 10^-2 m long, and Jun measured it before it flew away. How many meters is that, written as a decimal?

   0.01
2. 2.

   10^-3 = 1 ÷ (10 × 10 × 10): a 1 on top and 3 tens below the bar. A coin is about 10^-3 m thick. Kira stacked a few and they wobbled. How many meters is that, written as a decimal?

   0.001

3. Read this first

   Use this

   10^-4 = 1 ÷ (10 × 10 × 10 × 10): a 1 on top and 4 tens below the bar.

4. 3.

   A sheet of paper is about 10^-4 m thick, and Luz is not impressed. How many meters is that, written as a decimal?

   0.0001
5. 4.

   Milo's model rocket climbs 3 × 10^2 m high before it drops back into the grass. How many meters is that?

   300
6. 5.

   A forest has 4 × 10^3 trees, and Noah hugged one of them. How many trees are in the forest?

   4000
7. 6.

   The city bus line carries 6 × 10^3 riders each day, and Pia rides one of them. How many riders is that?

   6000

8. Use this

   2 × 10^-3 = 2 ÷ (10 × 10 × 10): a 2 on top and 3 tens below the bar.

9. 7.

   The lead in Tala's pencil is about 2 × 10^-3 m wide, and it snaps when pressed hard. How many meters is that, written as a decimal?

   0.002

10. Use this

    5 × 10^-4 = 5 ÷ (10 × 10 × 10 × 10): a 5 on top and 4 tens below the bar.

11. 8.

    Zee's pen draws a line about 5 × 10^-4 m wide, and the ink is running low. How many meters is that, written as a decimal?

    0.0005
12. 9.

    Esme's quiz card gives a gold star for the right answer. It shows three numbers, with strips of tens drawn. Which number is the greatest?

    • 3 × 10^-4
    • 7 × 10^-2
    • 5 × 10^-5
13. 10.

    Jun's phone shows three numbers, with the strips of tens drawn for each. Which number is the least?

    • 4 × 10^-5
    • 6 × 10^-2
    • 9 × 10^-3