Ответ:

  1. \(8\frac12+2\frac34=10\frac54=11\frac14\).
  2. \(3\frac16-1\frac23=2+\frac16-\frac46=1\frac12\).
  3. \(5\frac13-3\frac29=2+\frac39-\frac29=2\frac19\).