4) $$8^{-2}:0,5^4 = (2^3)^{-2}:(\frac{1}{2})^4 = 2^{-6}:2^{-4} = 2^{-6-(-4)} = 2^{-6+4} = 2^{-2} = \frac{1}{2^2} = \frac{1}{4}$$.
Ответ: $$\frac{1}{4}$$