Ответ:

  1. \(7\frac{1}{4}\cdot8=(7+\frac{1}{4})\cdot8=7\cdot8+\frac{1}{4}\cdot8=56+2=58\).
  2. \(5\frac{2}{5}\cdot6=(5+\frac{2}{5})\cdot6=5\cdot6+\frac{2}{5}\cdot6=30+\frac{12}{5}=32\frac{2}{5}\).

Ответ: а) 58; б) \(32\frac{2}{5}\).