16.35= 710

$$1\frac{6}{7} \cdot 3\frac{5}{10} = {\frac{13}{7}} \cdot {\frac{35}{10}} = {\frac{13 \cdot 35}{7 \cdot 10}} = {\frac{13 \cdot 5 \cdot 7}{7 \cdot 2 \cdot 5}} = {\frac{13}{2}} = 6\frac{1}{2}$$

Ответ: $$6\frac{1}{2}$$