④ a) \(1-\frac{3}{11}\) б) \(3-\frac{7}{18}\) в) \(5-2\frac{5}{7}\) г) \(11-7\frac{23}{31}\)

a) \(1-\frac{3}{11}\) = \(\frac{11}{11} - \frac{3}{11}\) = \(\frac{11-3}{11}\) = \(\frac{8}{11}\)

Ответ: \(\frac{8}{11}\)

б) \(3-\frac{7}{18}\) = \(\frac{3*18}{18} - \frac{7}{18}\) = \(\frac{54}{18} - \frac{7}{18}\) = \(\frac{54-7}{18}\) = \(\frac{47}{18}\) = \(\frac{36+11}{18}\) = \(\frac{2*18 + 11}{18}\) = \(2\frac{11}{18}\)

Ответ: \(2\frac{11}{18}\)

в) \(5-2\frac{5}{7}\) = \((5-2) - \frac{5}{7}\) = \(3 - \frac{5}{7}\) = \(\frac{3*7}{7} - \frac{5}{7}\) = \(\frac{21}{7} - \frac{5}{7}\) = \(\frac{21-5}{7}\) = \(\frac{16}{7}\) = \(\frac{2*7+2}{7}\) = \(2\frac{2}{7}\)

Ответ: \(2\frac{2}{7}\)

г) \(11-7\frac{23}{31}\) = \((11-7) - \frac{23}{31}\) = \(4 - \frac{23}{31}\) = \(\frac{4*31}{31} - \frac{23}{31}\) = \(\frac{124}{31} - \frac{23}{31}\) = \(\frac{124-23}{31}\) = \(\frac{101}{31}\) = \(\frac{3*31+8}{31}\) = \(3\frac{8}{31}\)

Ответ: \(3\frac{8}{31}\)