Using Standard Form

Question 1:

6.3 \times 10^{-6} + 5.6 \times 10^{-8}

6.356 \times 10^{-6}

Question 2:

3.5 \times 10^{5} - 5.7 \times 10^{4}

2.93 \times 10^{5}

Question 3:

1 \times 10^{-4} \times 4.3 \times 10^{-5}

4.3 \times 10^{-9}

Question 4:

\frac{7.2 \times 10^{5}}{5.6 \times 10^{-6}}

1.29 \times 10^{11}