\[\boxed{\mathbf{Страница\ 51.}еуроки - ответы\ на\ пятёрку}\]
\[\boxed{\mathbf{3.}}\]
\[\textbf{а)}\ \left( \frac{12}{13} + \frac{1}{13} \right) + \left( \frac{4}{16} + \frac{3}{16} \right) =\]
\[= 1 + \frac{7}{16} = 1\frac{7}{16}\]
\[\textbf{б)}\ \left( \frac{13}{50} + \frac{37}{50} \right) + \left( \frac{8}{27} + \frac{6}{27} \right) =\]
\[= 1 + \frac{14}{27} = 1\frac{14}{27}\]
\[\textbf{в)}\ \left( \frac{28}{33} - \frac{28}{33} \right) + \frac{2}{3} = \frac{2}{3}\]
\[\textbf{г)}\ \frac{6}{7} + \left( \frac{18}{19} - \frac{18}{19} \right) = \frac{6}{7}\]
\[\textbf{д)}\ \left( \frac{25}{57} - \frac{23}{57} \right) - \frac{2}{57} = \frac{2}{57} - \frac{2}{57} = 0\]
\[\textbf{е)}\ 2 - 2 = 0\]
\[\boxed{\mathbf{4.}}\]
\[\textbf{в)}\ 650 - (50 \cdot 3 + 60 \cdot 2) =\]
\[= 650 - 270 = 380\ (км) -\]
\[осталось\ пройти.\]
\[Ответ:380\ км.\]
\[\boxed{\mathbf{5.}}\]
\[\textbf{а)}\ 17\ 932\ :56 = 320\ (ост.\ 12)\]
\[320 \cdot 56 + 12 = 17\ 932\]
\[\textbf{б)}\ 487\ 120\ :687 = 709\ (ост.\ 37)\]
\[709 \cdot 687 + 37 = 487\ 120\]
\[\boxed{\mathbf{6.}}\]
\[20\ апреля - воскресенье.\]
\[Ответ:воскресенье.\]