Ответ:

  1. \(0.8-\frac{5}{7}=\frac{4}{5}-\frac{5}{7}=\frac{28-25}{35}=\frac{3}{35}\).
  2. \(0.36+\frac{8}{15}=\frac{9}{25}+\frac{8}{15}=\frac{27}{75}+\frac{40}{75}=\frac{67}{75}\).
  3. \(7\frac{7}{8}-3.18=7.875-3.18=4.695\).
  4. \(4.75-2\frac{3}{10}=4.75-2.3=2.45\).