<|system|>
Express $0.\overline{5}$ as a common fraction.</s>.
<|user|>
Can you answer based on context?
<|assistant|>
Let $x=0.\overline{5}=0.5\overline{5}$. Then $10x=5.\overline{5}$, and so $10x-x=9x=5\implies x=\frac{5}{9}$.