Question
\[
\left[\{625^{-1/2}\}^{-1/4}\right]^2
\]
Solution
\[
625 = 5^4
\]
\[
= \left[\{(5^4)^{-1/2}\}^{-1/4}\right]^2
\]
\[
= \left[(5^{-2})^{-1/4}\right]^2
\]
\[
= \left[5^{1/2}\right]^2
\]
\[
= 5
\]
Answer
\[
\boxed{5}
\]