\[\boxed{\mathbf{Проверочная\ работа\ №2.\ Сложение\ смешанных\ чисел}}\]
\[\boxed{\mathbf{1.}}\]
\[\frac{18}{27} = \frac{9 \cdot 2}{9 \cdot 3} = \frac{2}{3}.\]
\[\boxed{\mathbf{2.}}\]
\[\frac{23}{8} = 2\frac{7}{8}.\]
\[\boxed{\mathbf{3.}}\]
\[3\frac{4}{7} = \frac{3 \cdot 7 + 4}{7} = \frac{25}{7}.\]
\[\boxed{\mathbf{4.}}\]
\[2\frac{4}{9} + 5 = 7\frac{4}{9}.\]
\[\boxed{\mathbf{5.}}\]
\[\frac{1}{6} + 5\frac{2}{3} = \frac{1}{6} + 5\frac{4}{6} = 5\frac{5}{6}.\]
\[\boxed{\mathbf{6.}}\]
\[100\ мин = \frac{100}{60}\ ч = 1\frac{40}{60}\ ч =\]
\[= 1\frac{4}{6}\ ч = 1\frac{2}{3}\ ч.\]
\[\mathbf{Да.}\]
\[\boxed{\mathbf{7.}}\]
\[y + 2\frac{2}{5} = 4\]
\[y = 4 - 2\frac{2}{5} = 3\frac{5}{5} - 2\frac{2}{5}\]
\[y = 1\frac{3}{5}.\]
\[\mathbf{Нет.}\]
\[\boxed{\mathbf{8.}}\]
\[4\frac{3^{\backslash 6}}{5} + 3\frac{5^{\backslash 5}}{6} = 4\frac{18}{30} + 3\frac{25}{30} =\]
\[= 7\frac{43}{30} = 8\frac{13}{30} > 8.\]
\[\mathbf{Да.}\]