\(\frac{\left(5^4-5^3\right)^3}{125^4}=\frac{\left(5^1\right)^3}{244140625}=\frac{5^3}{244140625}\)
\(=\frac{125}{244140625}=\frac{1}{1953125}\)
\(\frac{\left(625-125\right)^3}{125^4}\)=\(\frac{500^3}{\left(5^3\right)^4}\)=\(\frac{\left(4.5^3\right)^3}{5^{12}}\)=\(\frac{4^3.5^9}{5^{12}}\)=\(\frac{4^3.5^9}{5^9.5^3}\)=\(\frac{4^3}{5^3}\)=\(\frac{64}{125}\)