Answer
$3$
Work Step by Step
Using $\log_bx^m=m\log_bx$ or the Power Rule of Logarithms, the given expression, $
\log_{10}1000
,$ is
\begin{array}{l}\require{cancel}
\log_{10}10^3
\\\\=
3\log_{10}10
.\end{array}
Since the $\log_bb=1,$ then the expression, $
3\log_{10}10
,$ simplifies to
\begin{array}{l}\require{cancel}
3(1)
\\\\=
3
.\end{array}