cube root? where is it on here?
$$\sqrt[3]{216} = 216^{(1/3)}$$
216^(1/3)
$${{\mathtt{216}}}^{\left({\frac{{\mathtt{1}}}{{\mathtt{3}}}}\right)} = {\mathtt{5.999\: \!999\: \!999\: \!999\: \!999}}$$
That is rounding error - The answer is 6