Using Standard Form

Question 1:

6.8 \times 10^{5} + 3 \times 10^{6}

3.68 \times 10^{6}

Question 2:

4 \times 10^{-3} - 3.2 \times 10^{-4}

3.68 \times 10^{-3}

Question 3:

4.7 \times 10^{6} \times 5.2 \times 10^{-3}

2.444 \times 10^{4}

Question 4:

\frac{2.5 \times 10^{4}}{9.2 \times 10^{6}}

2.72 \times 10^{-3}