$${{\mathtt{4}}}^{\left({\frac{{\mathtt{2}}}{{\mathtt{3}}}}\right)} = {{\left({{\mathtt{2}}}^{{\mathtt{2}}}\right)}}^{\left({\frac{{\mathtt{3}}}{{\mathtt{2}}}}\right)}$$ = $${{\mathtt{2}}}^{{\mathtt{3}}}$$
$${{\mathtt{16}}}^{{\mathtt{\,-\,}}\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)} = {\frac{{\mathtt{1}}}{\left({\left({{\mathtt{2}}}^{{\mathtt{4}}}\right)}^{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)}\right)}}$$ = $${\frac{{\mathtt{1}}}{{{\mathtt{2}}}^{{\mathtt{3}}}}}$$
$${\frac{{{\mathtt{2}}}^{{\mathtt{3}}}{\mathtt{\,\times\,}}{\mathtt{1}}}{{{\mathtt{2}}}^{{\mathtt{3}}}}} = {\mathtt{1}}$$
.
$${{\mathtt{4}}}^{\left({\frac{{\mathtt{2}}}{{\mathtt{3}}}}\right)} = {{\left({{\mathtt{2}}}^{{\mathtt{2}}}\right)}}^{\left({\frac{{\mathtt{3}}}{{\mathtt{2}}}}\right)}$$ = $${{\mathtt{2}}}^{{\mathtt{3}}}$$
$${{\mathtt{16}}}^{{\mathtt{\,-\,}}\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)} = {\frac{{\mathtt{1}}}{\left({\left({{\mathtt{2}}}^{{\mathtt{4}}}\right)}^{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)}\right)}}$$ = $${\frac{{\mathtt{1}}}{{{\mathtt{2}}}^{{\mathtt{3}}}}}$$
$${\frac{{{\mathtt{2}}}^{{\mathtt{3}}}{\mathtt{\,\times\,}}{\mathtt{1}}}{{{\mathtt{2}}}^{{\mathtt{3}}}}} = {\mathtt{1}}$$