г) 2\frac{1}{3} - 1\frac{1}{6} + 2\frac{7}{12}; д) -8\frac{1}{20} + 4\frac{4}{15} - 4,2; е) -4\frac{2}{5} + 3\frac{1}{2} - 6\frac{8}{15};

Ответ:

Решение:

г) \[2\frac{1}{3} - 1\frac{1}{6} + 2\frac{7}{12} = \frac{7}{3} - \frac{7}{6} + \frac{31}{12} = \frac{28}{12} - \frac{14}{12} + \frac{31}{12} = \frac{28-14+31}{12} = \frac{45}{12} = \frac{15}{4} = 3\frac{3}{4}\] д) \[-8\frac{1}{20} + 4\frac{4}{15} - 4,2 = -8\frac{1}{20} + 4\frac{4}{15} - 4\frac{2}{10} = -8\frac{3}{60} + 4\frac{16}{60} - 4\frac{12}{60} = -8\frac{3}{60} + \frac{256}{60} - \frac{252}{60} = -8\frac{3}{60} + \frac{4}{60} = -7\frac{63}{60} + \frac{4}{60} = -7\frac{59}{60}\] е) \[-4\frac{2}{5} + 3\frac{1}{2} - 6\frac{8}{15} = -4\frac{12}{30} + 3\frac{15}{30} - 6\frac{16}{30} = -4\frac{12}{30} + 3\frac{15}{30} - 6\frac{16}{30} = -\frac{132}{30} + \frac{105}{30} - \frac{96}{30} = -\frac{132 - 105 + 96}{30} = -\frac{123}{30} = -\frac{41}{10} = -4,1\]

Ответ: г) 3\frac{3}{4}; д) -7\frac{59}{60}; е) -4,1.