Answer
$0.000542$
Work Step by Step
Since the exponent of $10$ is $\text{
negative
}
4
,$ move the decimal point $
4
$ places to the $\text{
left.
}$ Hence, the given expression, $
5.42\times10^{-4}
$ is equivalent to
\begin{array}{l}\require{cancel}
0.000542
.\end{array}