To solve \( \frac{10}{15} - \frac{5}{15} \), we can subtract the numerators since the denominators are the same:
\[ \frac{10 - 5}{15} = \frac{5}{15} \]
Now, we can simplify \( \frac{5}{15} \) by dividing both the numerator and the denominator by their greatest common divisor, which is 5:
\[ \frac{5 \div 5}{15 \div 5} = \frac{1}{3} \]
Thus, the simplified result is
\[ \frac{1}{3}. \]