Answer
$0.000025$
Work Step by Step
Using the laws of exponents, the given expression, $
\dfrac{3\times10^{-2}}{12\times10^3}
,$ is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{3}{12}\times10^{-2-3}
\\\\=
\dfrac{1}{4}\times10^{-5}
\\\\=
0.25\times10^{-5}
.\end{array}
Since the exponent of $10$ is $\text{negative }
5
,$ move the decimal point $
5
$ places to the $\text{left.}$ Hence, the standard form of the expression above is
\begin{array}{l}\require{cancel}
0.000025
.\end{array}
