3 6 7 7

\[ \frac{3}{7} \div \frac{6}{7} = \frac{3}{7} \cdot \frac{7}{6} = \frac{3 \cdot 7}{7 \cdot 6} = \frac{21}{42} = \frac{1}{2} \]

Ответ: \(\frac{1}{2}\)