Tính

 $$\begin{gathered} A=\frac{{(-1)}^{2018}\times {\left(\begin{array}{c}2\\ 5\end{array}\right)}^3\times {\left(\begin{array}{c}15\\ 4\end{array}\right)}^2}{\frac{{15}^2}{2^4}} \\ B=\frac{6^8.4^2-4^4.{18}^4}{{27}^3.8^4-3^0.2^{10}.8} \end{gathered}$$