a) 45 - (-23) = 45 + 23 = 68
б) 26 - 39 = -13
в) -39.8 - (-23.5) = -39.8 + 23.5 = -16.3
г) -14.7 - 17.4 = -32.1
д) \(\frac{3}{7} - 4 = \frac{3}{7} - \frac{28}{7} = -\frac{25}{7}\)
e) \(-\frac{11}{12} - \left(-\frac{8}{9}\right) = -\frac{11}{12} + \frac{8}{9} = -\frac{33}{36} + \frac{32}{36} = -\frac{1}{36}\)
ж) \(-5\frac{3}{28} + 4\frac{5}{12} = -5\frac{9}{84} + 4\frac{35}{84} = -1 + \frac{-9 + 35}{84} = -1 + \frac{26}{84} = -1 + \frac{13}{42} = -\frac{42}{42} + \frac{13}{42} = -\frac{29}{42}\)
з) \(-3\frac{7}{12} - 2\frac{5}{8} = -3\frac{14}{24} - 2\frac{15}{24} = -5 - \frac{29}{24} = -5 - 1\frac{5}{24} = -6\frac{5}{24}\)