Ответ:

\(\frac{16}{25}:\frac{8}{21}=\frac{16}{25}\cdot\frac{21}{8}=\frac{42}{25}\).

\(\frac{7}{10}\cdot\frac{34}{35}=\frac{17}{25}\).

Ответ: \(\frac{16}{25}:\frac{8}{21}>\frac{7}{10}\cdot\frac{34}{35}\).