13) 9/5 · 2/3 =; 14) 5/3 · 9/2 =; 15) 5/6 − 3/14 =; 16) 6 1/2 − 17/10 =; 17) 3/5 − 2/7 =

1. \(\frac{9}{5}\cdot\frac{2}{3}=\frac{18}{15}=\frac{6}{5}=1.2\).
2. \(\frac{5}{3}\cdot\frac{9}{2}=\frac{45}{6}=\frac{15}{2}=7.5\).
3. \(\frac{5}{6}-\frac{3}{14}=\frac{35-9}{42}=\frac{26}{42}=\frac{13}{21}\).
4. \(6\frac{1}{2}-\frac{17}{10}=\frac{65}{10}-\frac{17}{10}=\frac{48}{10}=\frac{24}{5}=4.8\).
5. \(\frac{3}{5}-\frac{2}{7}=\frac{21-10}{35}=\frac{11}{35}\).

Ответ: 13) 1.2; 14) 7.5; 15) 13/21; 16) 4.8; 17) 11/35.