# How do you multiply (4 x 10^3)(0.2 x 10^3) and write your answer in scientific notation?

Assuming the $x$'s in your question are meant to be multiplication signs (use xx to get a single multiplication sign inside hashtags)
$\left(4 \times {10}^{3}\right) \cdot \left(0.2 \times {10}^{3}\right)$ can be re-arranged as
$\left(4 \times 0.2\right) \times \left({10}^{3} \times {10}^{3}\right)$
$= 0.8 \times {10}^{6}$