L22 · Scientific notation

1. 1.

   Write 160000 in scientific notation.

   Answer. 1.6 × 10^5

   Coefficient 1.6 with 10^5.

2. 2.

   Compute (7.0 × 10^4) × (2 × 10^2). Write in scientific notation.

   Answer. 1.40 × 10^7

   Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10.

3. 3.

   Write 5400000 in scientific notation.

   Answer. 5.4 × 10^6

   Coefficient 5.4 with 10^6.

4. 4.

   Compute (7.4 × 10^6) × (2 × 10^2). Write in scientific notation.

   Answer. 1.48 × 10^9

   Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10.

5. 5.

   Write 63000 in scientific notation. Then Ava needs 3 of that amount. What is the total they need?

   Answer. 18.9 × 10^4

   Coefficient 6.3 with 10^4. Then multiply by 3: 18.9 × 10^4.

6. 6.

   Compute (5.3 × 10^5) × (2 × 10^2). Write in scientific notation. Then Ava needs 4 of that amount. What is the total they need?

   Answer. 4.24 × 10^8

   Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10. Then multiply by 4: 4.24 × 10^8.

7. 7.

   Write 2900000 in scientific notation. Then Mei needs 3 of that amount. What is the total they need?

   Answer. 8.7 × 10^6

   Coefficient 2.9 with 10^6. Then multiply by 3: 8.7 × 10^6.

8. 8.

   Compute (6.3 × 10^5) × (2 × 10^2). Write in scientific notation. Then Mei needs 3 of that amount. What is the total they need?

   Answer. 3.78 × 10^8

   Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10. Then multiply by 3: 3.78 × 10^8.

9. 9.

   Write 25000 in scientific notation. Then Sam needs 5 of that amount. What is the total they need?

   Answer. 12.5 × 10^4

   Coefficient 2.5 with 10^4. Then multiply by 5: 12.5 × 10^4.

10. 10.

    Compute (5.3 × 10^3) × (2 × 10^2). Write in scientific notation. Then Sam needs 3 of that amount. What is the total they need?

    Answer. 3.18 × 10^6

    Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10. Then multiply by 3: 3.18 × 10^6.

11. 11.

    Think

    Jonah tried this problem:
    Write 820000 in scientific notation.
    Jonah wrote 16.4 × 10^5. That is not correct. What is the right answer?

    Answer. 8.2 × 10^5

    Jonah’s answer 16.4 × 10^5 is off. Coefficient 8.2 with 10^5.

12. 12.

    Think

    Ava tried this problem:
    Compute (3.0 × 10^4) × (2 × 10^2). Write in scientific notation.
    Ava wrote -6 × 10^6. That is not correct. What is the right answer?

    Answer. 6.0 × 10^6

    Ava’s answer -6 × 10^6 is off. Multiply coefficients and add exponents, then adjust so the coefficient is at least 1 and less than 10.

Original extra practice. Keys are computed from the items, not guessed.