Answer:
Step-by-step explanation:
[tex](2\times10^{-2})(4\times10^{-3})\\\\=(2\times4)(10^{-2}\times10^{-4})\qquad\text{use}\ a^n\times a^m=a^{n+m}\\\\=8\times10^{-2+(-4)}\\\\=8\times10^{-6}[/tex]