To divide the fraction \( \frac{8}{9} \) by 5, you can rewrite the division as multiplication by the reciprocal:
\[ \frac{8}{9} \div 5 = \frac{8}{9} \times \frac{1}{5} \]
Now, you multiply the numerators and the denominators:
\[ \frac{8 \times 1}{9 \times 5} = \frac{8}{45} \]
The fraction \( \frac{8}{45} \) is already in its simplest form, as there are no common factors between 8 and 45.
So, the final answer is:
\[ \frac{8}{45} \]