Answer
$2.7\times10^{-3}$
Work Step by Step
Using $a\times10^n$, where $1\le a\le9,$ and $n$ is an integer, the scientific notation of the given expression, $
0.0027
,$ is
\begin{array}{l}\require{cancel}
2.7
\div1000
\\\\=
2.7\times10^{-3}
.\end{array}