What is 0.0081 whole power 3/4
$$\\0.0081^{3/4}\\\\ =(0.0081^{1/4})^3\\\\ =0.3^3\\\\ =0.027$$
check
$${{\mathtt{0.008\: \!1}}}^{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)} = {\frac{{\mathtt{27}}}{{\mathtt{1\,000}}}} = {\mathtt{0.027}}$$
4.477777777 etc.