\[( - 0,5)^{3} = - \left( \frac{5}{10} \right)^{3} = - \frac{5^{3}}{10^{3}} =\]
\[= - \frac{5^{2} \cdot 5}{10^{2} \cdot 10} = - \frac{25 \cdot 5}{100 \cdot 10} =\]
\[= - \frac{125}{1000} = - 0,125.\]