Scientific notation: write, convert and say how many times larger

Answer Key - Grade 8 Math Worksheet - Challenge Me

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

1. 1.

   Tala reads that a heart beats about 3 × 10^9 times in a long life and 6 × 10^4 times in half a day. How many times as many beats is a life?

   5 × 10^4
2. 2.

   In Ari's notes, a hair is 4 × 10^-5 m wide and a virus is 8 × 10^-8 m across. How many times as wide is the hair?

   5 × 10^2
3. 3.

   Bo reads that 8,100,000,000 people live on Earth and 2,100,000 in a big city. Rounding each to one digit, about how many times as many?

   4 × 10^3
4. 4.

   Esme reads that the Sun is 1,392,000 km across and Earth 12,742 km. Rounding each to one digit, about how many times as wide is the Sun?

   1 × 10^2
5. 5.

   Luz's calculator shows 47 × 10^6. Write it in scientific notation, then round it to one digit. What do you get?

   5 × 10^7
6. 6.

   Milo's calculator shows 0.38 × 10^-4. Write it in scientific notation, then round it to one digit. What do you get?

   4 × 10^-5
7. 7.

   In Pia's science notes, a grown-up body has about 37,000,000,000,000 cells. What is that, rounded to one digit times a power of 10?

   4 × 10^13
8. 8.

   Bo reads that light travels about 9,460,000,000,000 km in a year. What is that, rounded to one digit times a power of 10?

   9 × 10^12
9. 9.

   In Esme's science notes, a tiny particle is about 0.0000000003 m across. What is that as one digit times a power of 10?

   3 × 10^-10
10. 10.

    In Luz's science notes, a sheet of gold leaf is about 0.00000012 m thick. What is that, rounded to one digit times a power of 10?

    1 × 10^-7