\[\boxed{\mathbf{Проверочная\ работа\ №1.\ Сложение\ и\ вычитание\ обыкновенных\ дробей}}\]
\[\boxed{\mathbf{1.}}\]
\[\frac{2}{9} = \frac{4}{18}\ и\ \frac{7}{18}.\]
\[\boxed{\mathbf{2.}}\]
\[\frac{3^{\backslash 2}}{10} + \frac{7}{20} = \frac{6}{20} + \frac{7}{20} = \frac{13}{20}.\]
\[\boxed{\mathbf{3.}}\]
\[\frac{1^{\backslash 3}}{2} + \frac{1^{\backslash 2}}{3} = \frac{3}{6} + \frac{2}{6} = \frac{5}{6}.\]
\[\boxed{\mathbf{4.}}\]
\[\frac{4^{\backslash 2}}{7} - \frac{3}{14} = \frac{8}{14} - \frac{3}{14} = \frac{5}{14}\]
\[\boxed{\mathbf{5.}}\]
\[\frac{1^{\backslash 4}}{3} - \frac{1^{\backslash 3}}{4} = \frac{4}{12} - \frac{3}{12} = \frac{1}{12}\]
\[\boxed{\mathbf{6.}}\]
\[\frac{1^{\backslash 2}}{2} + \frac{1}{4} = \frac{2}{4} + \frac{1}{4} = \frac{3}{4} < 1\]
\[Да.\]
\[\boxed{\mathbf{7.}}\]
\[\frac{1^{\backslash 2}}{2} - \frac{1}{4} = \frac{2}{4} - \frac{1}{4} = \frac{1}{4} =\]
\[= 25\% > 20\%.\]
\[Верно.\]
\[\boxed{\mathbf{8.}}\]
\[\mathbf{Нет,\ она\ имеет\ простой\ }\]
\[\mathbf{числитель\ и\ четный\ }\]
\[\mathbf{знаменатель.}\]