Давай выполним вычитание в каждом пункте:
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 = \(\frac{3}{7}\) - \(\frac{28}{7}\) = -\(\frac{25}{7}\) = -3\(\frac{4}{7}\)
е) \(\frac{11}{12}\) - (-\(\frac{8}{9}\)) = \(\frac{11}{12}\) + \(\frac{8}{9}\) = \(\frac{33}{36}\) + \(\frac{32}{36}\) = \(\frac{65}{36}\) = 1\(\frac{29}{36}\)
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 + \(\frac{13}{42}\) = -\(\frac{29}{42}\)
з) -3\(\frac{5}{12}\) - 2\(\frac{5}{8}\) = -3\(\frac{10}{24}\) - 2\(\frac{15}{24}\) = -5\(\frac{25}{24}\) = -6\(\frac{1}{24}\)
Ответ: а) 68; б) -13; в) -16,3; г) -32,1; д) -3\(\frac{4}{7}\); е) 1\(\frac{29}{36}\); ж) -\(\frac{29}{42}\); з) -6\(\frac{1}{24}\)
Ты молодец! У тебя все отлично получается!