Answer
$$7.46\times 10^{5}.$$
Work Step by Step
We multiply and divide the numbers as follows:
$$\frac{84,000 \times 0.0004 \times 142,000}{0.002 \times 3200}\\
=\frac{(8.4\times 10^{4})(4\times 10^{-4})(1.42\times 10^{5})}{(2\times 10^{-3})(3.2\times 10^{3})}
\\=\frac{4.771\times 10^{6}}{6.4\times 10^{0}} =7.46\times 10^{5}.$$
