Answer
$5.0\times10^{-2}$
Work Step by Step
Using scientific notation and the laws of exponents, the given expression, $
\dfrac{0.0000035\times4000}{0.28}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{(3.5\times10^{-6})\times(4.0\times10^3)}{2.8\times 10^{-1}}
\\\\=
(3.5\times4.0\div2.8)\times(10^{-6}\cdot10^{3}\div10^{-1})
\\\\=
5.0\times10^{-6+3-(-1)}
\\\\=
5.0\times10^{-6+3+1}
\\\\=
5.0\times10^{-2}
.\end{array}
