Ответ:

  1. \( -\frac{3}{4}-\left(-\frac{5}{6}\right)=-\frac{3}{4}+\frac{5}{6}=-\frac{9}{12}+\frac{10}{12}=\frac{1}{12}\).
  2. \(25-32=-7\).
  3. \(3\frac{5}{6}-4\frac{3}{8}=\frac{23}{6}-\frac{35}{8}=\frac{92-105}{24}=-\frac{13}{24}\).
  4. \(-3-\frac{4}{9}=-\frac{27}{9}-\frac{4}{9}=-\frac{31}{9}=-3\frac{4}{9}\).
  5. \(-5.5-2.8=-8.3\).
  6. \(-7\frac{8}{9}-\left(-9\frac{1}{6}\right)=-7\frac{8}{9}+9\frac{1}{6}=1\frac{5}{18}\).

Ответ: а) \(\frac{1}{12}\); б) \(-7\); в) \(-\frac{13}{24}\); г) \(-3\frac{4}{9}\); д) \(-8,3\); е) \(1\frac{5}{18}\).