Решебник по математике 6 класс Мерзляк ФГОС Задание 969

\[\boxed{\mathbf{969\ (}\mathbf{н}\mathbf{).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1) - \frac{1}{4} + \frac{3}{5} = - \frac{5}{20} + \frac{12}{20} = \frac{7}{20}\]

\[2)\ \frac{9}{11} + \left( - \frac{2}{5} \right) = \frac{45}{55} - \frac{22}{55} = \frac{23}{55}\]

\[3) - \frac{20}{21} + \frac{3}{7} = - \frac{20}{21} + \frac{9}{21} = - \frac{11}{21}\]

\[4)\ 7\frac{5}{12} + \left( - 3\frac{7}{24} \right) = 7\frac{10}{24} -\]

\[- 3\frac{7}{24} = 4\frac{3}{24} = 4\frac{1}{8}\]

\[5) - 6\frac{11}{12} + \left( - 8\frac{13}{18} \right) = - 6\frac{33}{36} -\]

\[- 8\frac{26}{36} = - 14\frac{59}{36} = - 15\frac{23}{36}\]

\[6) - 5\frac{12}{35} + 10 = 9\frac{35}{35} -\]

\[- 5\frac{12}{35} = 4\frac{23}{25}\]

\[7) - 3\frac{1}{12} + \frac{1}{6} = - 2\frac{13}{12} +\]

\[+ \frac{2}{12} = - 2\frac{11}{12}\]

\[8)\ 3\frac{6}{7} + \left( - 6\frac{4}{9} \right) = 3\frac{54}{63} -\]

\[- 5\frac{91}{63} = - 2\frac{37}{63}\]

\[9)\ 9\frac{1}{6} + \left( - 5\frac{3}{4} \right) = 8\frac{14}{12} -\]

\[- 5\frac{9}{12} = 3\frac{5}{12}\]