Решебник по математике 5 класс Ерина Виленкин рабочая тетрадь Часть 1, 2 Часть 2 | Страница 46

\[Стр.\ 46.\]

\[\boxed{\mathbf{6.}}\]

\[\textbf{а)}\ \frac{1}{6} + \frac{5}{9} + \frac{5}{6} + \frac{4}{9} = \frac{6}{6} + \frac{9}{9} =\]

\[= 1 + 1 = 2\]

\[\textbf{б)}\ \frac{2}{17} + \frac{3}{8} + \frac{5}{17} + \frac{10}{17} + \frac{5}{8} =\]

\[= \frac{17}{17} + \frac{8}{8} = 1 + 1 = 2\]

\[\textbf{в)}\ \frac{1}{12} + \frac{1}{16} + \frac{5}{12} + \frac{7}{16} =\]

\[= \frac{6}{12} + \frac{8}{16} = \frac{1}{2} + \frac{1}{2} = 1\]

\[\textbf{г)}\ \frac{3}{17} + \frac{4}{5} + \frac{1}{15} + \frac{14}{17} =\]

\[= \frac{17}{17} + \frac{12}{15} + \frac{1}{15} = 1 + \frac{13}{15} =\]

\[= 1\frac{13}{15}\]

\[\boxed{\mathbf{7.}}\]

\[\textbf{а)}\ x + \frac{3}{16} = \frac{17}{20}\]

\[x = \frac{17}{20} - \frac{3}{16}\]

\[x = \frac{68}{80} - \frac{15}{80}\]

\[x = \frac{53}{80}.\]

\[\textbf{б)}\ \frac{8}{15} + y = \frac{7}{12}\]

\[y = \frac{7}{12} - \frac{8}{15}\]

\[y = \frac{35}{60} - \frac{32}{60}\]

\[y = \frac{3}{60} = \frac{1}{20}.\]

\[\textbf{в)}\ a - \frac{1}{12} = \frac{7}{30}\]

\[a = \frac{7}{30} + \frac{1}{12}\]

\[a = \frac{14}{60} + \frac{5}{60}\]

\[a = \frac{19}{60}.\]

\[\textbf{г)}\ \frac{25}{39} - b = \frac{15}{26}\]

\[b = \frac{25}{39} - \frac{15}{26}\]

\[b = \frac{50}{78} - \frac{45}{78}\]

\[b = \frac{5}{78}.\]

\[\boxed{\mathbf{8.}}\]

\[\textbf{а)}\ \frac{7}{10} - \frac{1}{5} = \frac{7}{10} - \frac{2}{10} = \frac{5}{10} =\]

\[= \frac{1}{2}\ (м) - провода\ осталось.\]

\[Ответ:\ \frac{1}{2}\ м.\]

\[\textbf{б)}\ \frac{2}{5} + \frac{3}{4} = \frac{8}{20} + \frac{15}{20} = \frac{23}{20} =\]

\[= 1\frac{3}{20}\ (кг) - масса\ покупки.\]

\[Ответ:\ \ 1\frac{3}{20}\ кг\]

\[\textbf{в)}\ \frac{2}{3} + \frac{1}{5} = \frac{10}{15} + \frac{3}{15} = \frac{13}{15}\ ч =\]

\[= \frac{52}{60}\ ч = 52\ мин - потратила\ \]

\[Оля.\]

\[Ответ:52\ мин.\]

\[\textbf{г)}\ \ 1 - все\ поле;\]

\[\frac{1}{6}\ часть - первый\ трактор;\]

\[\frac{1}{9}\ часть - второй\ трактор.\]

\[\frac{1}{6} + \frac{1}{9} = \frac{3}{18} + \frac{2}{18} = \frac{5}{18}\ (часть) -\]

\[поля\ вспашут\ оба\ трактора\ \]

\[за\ 1\ день.\]

\[Ответ:\ \frac{5}{18}\ часть\ поля.\]