42 7 3 60 12 21

\[ \frac{42}{60} \div \frac{7}{12} \div \frac{3}{21} = \frac{42}{60} \cdot \frac{12}{7} \cdot \frac{21}{3} = \frac{42 \cdot 12 \cdot 21}{60 \cdot 7 \cdot 3} = \frac{10584}{1260} = \frac{126}{15} = 8\frac{2}{5} \]

Ответ: \(8\frac{2}{5}\)