What is $0.8\overline{4}-0.\overline{4}$? Express your answer as a common fraction.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
What is $0.8\overline{4}-0.\overline{4}$? Express your answer as a common fraction.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
\frac{2}{5}
What is $0.8\overline{4}-0.\overline{4}$? Express your answer as a common fraction.
train