\[\mathbf{Страница\ 94.}\]
\[\boxed{\mathbf{5.}}\]
\[\textbf{а)} - \frac{1}{6} + \frac{13}{18} - \frac{7}{18} = - \frac{1}{6} + \frac{6}{18} =\]
\[= - \frac{1}{6} + \frac{2}{6} = \frac{1}{6}\]
\[- \frac{4}{49} - \frac{2}{7} - \frac{3}{47} = - \frac{7}{49} - \frac{2}{7} =\]
\[= - \frac{1}{7} - \frac{2}{7} = - \frac{3}{7}\]
\[- \frac{1}{8} + \frac{5}{24} - \frac{3}{8} = - \frac{4}{8} + \frac{5}{24} =\]
\[= - \frac{12}{24} + \frac{5}{24} = - \frac{7}{24}\]
\[\frac{5}{12} - \frac{7}{8} - \frac{7}{24} = \frac{10}{24} - \frac{21}{24} - \frac{7}{24} =\]
\[= - \frac{18}{24} = - \frac{3}{4}\]
\[\textbf{б)} - \frac{2}{7} + \frac{1}{21} - \frac{2}{21} = - \frac{6}{21} - \frac{1}{21} =\]
\[= - \frac{7}{21} = - \frac{1}{3}\]
\[\frac{25}{48} - \frac{5}{6} - \frac{3}{8} = \frac{25}{48} - \frac{40}{48} - \frac{18}{48} =\]
\[= - \frac{33}{48} = - \frac{11}{16}\]
\[- \frac{5}{169} - \frac{1}{13} - \frac{151}{169} =\]
\[= - \frac{13}{169} - \frac{156}{169} = - \frac{169}{169} = - 1\]
\[\frac{3}{14} - \frac{6}{7} - \frac{1}{42} = \frac{9}{42} - \frac{36}{42} - \frac{1}{42} =\]
\[= - \frac{28}{42} = - \frac{2}{3}\]
\[\boxed{\mathbf{6.}}\]
\[\textbf{а)}\ \frac{1}{2} + \left( \frac{7}{12} - \frac{5}{6} \right) =\]
\[= \frac{6}{12} + \frac{7}{12} - \frac{10}{12} = \frac{3}{12} = \frac{1}{4}\]
\[- \frac{1}{12} + \left( \frac{11}{18} - \frac{4}{9} \right) =\]
\[= - \frac{1}{12} + \frac{11}{18} - \frac{8}{18} =\]
\[= - \frac{1}{12} + \frac{3}{18} = - \frac{1}{12} + \frac{1}{6} =\]
\[= - \frac{1}{12} + \frac{2}{12} = \frac{1}{12}\]
\[\frac{7}{18} + \left( \frac{11}{18} - \frac{1}{6} \right) = \frac{7}{18} + \frac{11}{18} - \frac{1}{6} =\]
\[= \frac{18}{18} - \frac{1}{6} = 1 - \frac{1}{6} = \frac{5}{6}\]
\[\frac{3}{44} + \left( - \frac{11}{44} + \frac{5}{22} \right) =\]
\[= \frac{3}{44} - \frac{11}{44} + \frac{5}{22} =\]
\[= - \frac{8}{44} + \frac{5}{22} = - \frac{4}{22} + \frac{5}{22} = \frac{1}{22}\]
\[- \frac{3}{16} - \left( \frac{5}{16} - \frac{3}{8} \right) =\]
\[= - \frac{3}{16} - \frac{5}{16} + \frac{3}{8} =\]
\[= - \frac{8}{16} + \frac{3}{8} = - \frac{4}{8} + \frac{3}{8} = - \frac{1}{8}\]
\[\textbf{б)} - \frac{1}{48} + \left( \frac{7}{12} - \frac{3}{4} \right) =\]
\[= - \frac{1}{48} + \frac{28}{48} - \frac{36}{48} = - \frac{9}{48}\]
\[\left( - \frac{1}{14} - \frac{3}{7} \right) + \frac{1}{4} =\]
\[= \left( - \frac{1}{14} - \frac{6}{14} \right) + \frac{1}{4} =\]
\[= - \frac{7}{14} + \frac{1}{4} = - \frac{1}{2} + \frac{1}{4} =\]
\[= - \frac{2}{4} + \frac{1}{4} = - \frac{1}{4}\]
\[\left( - \frac{3}{16} + \frac{1}{2} \right) - \frac{3}{8} =\]
\[= - \frac{3}{16} + \frac{8}{16} - \frac{6}{16} = - \frac{1}{16}\]
\[- \left( \frac{3}{8} - \frac{11}{12} \right) + \frac{1}{24} =\]
\[= - \frac{9}{24} + \frac{22}{24} + \frac{1}{24} =\]
\[= - \frac{14}{24} = - \frac{7}{12}\]
\[- \left( \frac{2}{15} + \frac{4}{5} \right) + \frac{3}{10} =\]
\[= - \frac{4}{30} - \frac{24}{30} + \frac{9}{30} = - \frac{19}{30}\]
\[\boxed{\mathbf{7.}}\]
\[\textbf{а)}\ 3 \cdot \left( \frac{1}{9} - \frac{1}{3} \right) = 3 \cdot \left( \frac{1}{9} - \frac{3}{9} \right) =\]
\[= 3 \cdot \left( - \frac{2}{9} \right) = - \frac{2}{3}\]
\[\left( \frac{1}{14} - \frac{1}{7} \right) \cdot ( - 7) =\]
\[= \left( \frac{1}{14} - \frac{2}{14} \right) \cdot ( - 7) =\]
\[= - \frac{1}{14} \cdot ( - 7) = \frac{1}{2}\]
\[\frac{1}{5} \cdot \left( \frac{5}{7} - \frac{5}{8} \right) = \frac{1}{5} \cdot \frac{5}{7} - \frac{1}{5} \cdot \frac{5}{8} =\]
\[= \frac{1}{7} - \frac{1}{8} = \frac{8}{56} - \frac{7}{56} = \frac{1}{56}\]
\[- \frac{1}{4} \cdot \left( \frac{4}{11} - \frac{4}{13} \right) =\]
\[= - \frac{1}{4} \cdot \frac{4}{11} + \frac{1}{4} \cdot \frac{4}{13} =\]
\[= - \frac{1}{11} + \frac{1}{13} = - \frac{13}{143} + \frac{11}{143} =\]
\[= - \frac{2}{143}\]
\[\textbf{б)}\ 5 \cdot \left( \frac{1}{10} - \frac{1}{5} \right) = 5 \cdot \left( \frac{1}{10} - \frac{2}{10} \right) =\]
\[= 5 \cdot \left( - \frac{1}{10} \right) = - \frac{1}{2}\]
\[\left( \frac{1}{18} - \frac{1}{6} \right) \cdot ( - 6) =\]
\[= \left( \frac{1}{18} - \frac{3}{18} \right) \cdot ( - 6) =\]
\[= - \frac{2}{18} \cdot ( - 6) = \frac{2}{3}\]
\[\frac{1}{8} \cdot \left( \frac{8}{13} - \frac{8}{15} \right) = \frac{1}{8} \cdot \frac{8}{13} - \frac{1}{8} \cdot \frac{8}{15} =\]
\[= \frac{1}{13} - \frac{1}{15} = \frac{15}{195} - \frac{13}{195} = \frac{2}{195}\]
\[- \frac{1}{6} \cdot \left( \frac{6}{7} - \frac{6}{11} \right) =\]
\[= - \frac{1}{6} \cdot \frac{6}{7} + \frac{1}{6} \cdot \frac{6}{11} =\]
\[= - \frac{1}{7} + \frac{1}{11} = - \frac{11}{77} + \frac{7}{77} = - \frac{4}{77}\]
\[\boxed{\mathbf{8.}}\]
\[Ответ:\]
\[каждый\ работал\ по\ 10\ дней.\]