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Math Grade 6-8 Answer Key

Math: Scientific Notation

Writing very large and very small numbers with powers of 10

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Math: Scientific Notation

Writing very large and very small numbers with powers of 10

Math - Grade 6-8

Instructions: Read each problem carefully. Write each answer clearly and show your work when needed.
  1. 1

    Write 4,500 in scientific notation.

    Move the decimal so the first factor is at least 1 but less than 10.

    The number 4,500 in scientific notation is 4.5 x 10^3 because the decimal moves 3 places to the left.
  2. 2

    Write 0.0072 in scientific notation.

    The number 0.0072 in scientific notation is 7.2 x 10^-3 because the decimal moves 3 places to the right to make 7.2.
  3. 3

    Write 8.3 x 10^5 in standard form.

    A positive exponent means move the decimal to the right.

    The number 8.3 x 10^5 in standard form is 830,000 because the decimal moves 5 places to the right.
  4. 4

    Write 6.1 x 10^-4 in standard form.

    The number 6.1 x 10^-4 in standard form is 0.00061 because the decimal moves 4 places to the left.
  5. 5

    Write 92,000,000 in scientific notation.

    The first number in scientific notation must be at least 1 but less than 10.

    The number 92,000,000 in scientific notation is 9.2 x 10^7 because the decimal moves 7 places to the left.
  6. 6

    Write 0.00000045 in scientific notation.

    The number 0.00000045 in scientific notation is 4.5 x 10^-7 because the decimal moves 7 places to the right.
  7. 7

    Which number is greater: 3.2 x 10^4 or 3.2 x 10^5? Explain.

    Compare the exponents when the first factors are the same.

    The greater number is 3.2 x 10^5 because both numbers have the same first factor, and 10^5 is 10 times larger than 10^4.
  8. 8

    Which number is smaller: 7.9 x 10^-2 or 7.9 x 10^-5? Explain.

    The smaller number is 7.9 x 10^-5 because a more negative exponent means the decimal value is smaller when the first factors are the same.
  9. 9

    Write 5,670,000,000 in scientific notation.

    Count how many places the decimal moves from the end of the whole number.

    The number 5,670,000,000 in scientific notation is 5.67 x 10^9 because the decimal moves 9 places to the left.
  10. 10

    Write 0.00032 in scientific notation.

    The number 0.00032 in scientific notation is 3.2 x 10^-4 because the decimal moves 4 places to the right.
  11. 11

    Write 1.04 x 10^6 in standard form.

    Use zeros as placeholders if needed.

    The number 1.04 x 10^6 in standard form is 1,040,000 because the decimal moves 6 places to the right.
  12. 12

    Write 9.8 x 10^-3 in standard form.

    The number 9.8 x 10^-3 in standard form is 0.0098 because the decimal moves 3 places to the left.
  13. 13

    Is 12.4 x 10^3 written correctly in scientific notation? If not, rewrite it correctly.

    Check whether the first number is at least 1 but less than 10.

    No, 12.4 x 10^3 is not written correctly because the first factor must be less than 10. The correct scientific notation is 1.24 x 10^4.
  14. 14

    Is 0.6 x 10^8 written correctly in scientific notation? If not, rewrite it correctly.

    No, 0.6 x 10^8 is not written correctly because the first factor must be at least 1. The correct scientific notation is 6 x 10^7.
  15. 15

    A bacterium is 0.000005 meters long. Write this length in scientific notation.

    Very small numbers use negative exponents.

    The length in scientific notation is 5 x 10^-6 meters because the decimal moves 6 places to the right to make 5.
LivePhysics.com Math - Grade 6-8 - Answer Key