Answer
$4$
Work Step by Step
Using the definition of rational exponents which is given by $a^{\frac{m}{n}}=\sqrt[n]{a^m}=\left(\sqrt[n]{a}\right)^m,$ the given expression, $
8^{2/3}
,$ is equivalent to
\begin{array}{l}\require{cancel}
\left( \sqrt[3]{8} \right)^2
\\\\=
\left( 2 \right)^2
\\\\=
4
.\end{array}
