Using Standard Form

Question 1:

5.7 \times 10^{-6} + 1 \times 10^{-5}

1.57 \times 10^{-5}

Question 2:

7.2 \times 10^{6} - 4.9 \times 10^{4}

7.151 \times 10^{6}

Question 3:

3.3 \times 10^{-6} \times 3.2 \times 10^{3}

1.056 \times 10^{-2}

Question 4:

\frac{2.1 \times 10^{6}}{7.3 \times 10^{-4}}

2.88 \times 10^{9}