From Förberedande kurs i matematik 1

The partial expression \displaystyle 2^{2^{3}} should be interpreted as 2 raised to the \displaystyle 2^{3}, and because \displaystyle 2^{3}=2\cdot 2\cdot 2=8, thus \displaystyle 2^{2^{3}}=2^{8}.

In order to calculate the next part of the expression, \displaystyle (-2)^{-4}, it can be useful to do it a step at a time

\displaystyle \begin{align} (-2)^{-4} &= \frac{1}{(-2)^{4}} = \frac{1}{((-1)\cdot 2)^{4}} = \frac{1}{(-1)^{4}\cdot 2^{4}}\\[5pt] &= \frac{1}{1\cdot 2^{4}} = \frac{1}{2^{4}} = 2^{-4}\,\textrm{.} \end{align}

Thus,

\displaystyle 2^{2^{3}}\cdot (-2)^{-4} = 2^{8}\cdot 2^{-4} = 2^{8-4} = 2^{4} = 16\,.