what is (5) exposant -3
$${{\mathtt{5}}}^{-{\mathtt{3}}} = {\frac{{\mathtt{1}}}{{\mathtt{125}}}} = {\mathtt{0.008}}$$
That's because (imagine n is any number): n^-e= 1/n^e
So for example: 6^-2 = 1/6^2 or 1/36