### Instruction: Express $3.\overline{7}$ as a common fraction.### Response: I know that repeating decimals can be converted to fractions by using a clever trick.
If I let $x = 3.\overline{7}$, then I can multiply both sides by 10 to get $10x = 37.\overline{7}$.
Then I can subtract $x$ from $10x$ to eliminate the repeating part and get $9x = 34$.
Solving for $x$, I get $x = \frac{34}{9}$.
This is the fraction equivalent of $3.\overline{7}$.