To convert the mixed number \( 7 \frac{8}{9} \) into an improper fraction, you can follow these steps:
- Multiply the whole number by the denominator: \( 7 \times 9 = 63 \).
- Add the numerator to the result from step 1: \( 63 + 8 = 71 \).
- Write the result from step 2 over the original denominator:
\[ \frac{71}{9} \]
Therefore, the improper fraction form of \( 7 \frac{8}{9} \) is \( \frac{71}{9} \).