Ответ:

  1. \(15+5-3=17\).
  2. \(38-28+18=28\).
  3. \(\frac{6}{9}-\frac{1}{2}=\frac{1}{6}\).
  4. \(\frac{15}{16}\cdot\frac45-\frac{5}{12}\cdot\frac45+\frac52\cdot\frac45=\frac34-\frac13+2=\frac{29}{12}\).

Ответ: 1) \(17\); 2) \(28\); 3) \(\frac{1}{6}\); 4) \(\frac{29}{12}\).