Using Standard Form

Question 1:

1.7 \times 10^{-4} + 6.8 \times 10^{-5}

2.38 \times 10^{-4}

Question 2:

7 \times 10^{-5} - 4 \times 10^{-6}

6.6 \times 10^{-5}

Question 3:

4.9 \times 10^{-4} \times 9 \times 10^{-5}

4.41 \times 10^{-8}

Question 4:

\frac{7.4 \times 10^{-5}}{7.9 \times 10^{-6}}

9.37 \times 10^{0}