$2^{-3}$
\(\boxed{2^{-3} = 0.125}\)
Step 1 :Calculate the reciprocal of \(2^3\): \(\frac{1}{2^3}\)
Step 2 :\(\frac{1}{2^3} = \frac{1}{8}\)
Step 3 :\(\frac{1}{8} = 0.125\)
Step 4 :\(\boxed{2^{-3} = 0.125}\)