\[Стр.\ 32.\]
\[\boxed{\mathbf{7.}}\]
\[\textbf{а)}\ 9 - 2\frac{1}{5} = 8\frac{5}{5} - 2\frac{1}{5} = 6\frac{4}{5}\ \]
\[\textbf{б)}\ 3 - \frac{1}{3} = 2\frac{3}{3} - \frac{1}{3} = 2\frac{2}{3}\]
\[\textbf{в)}\ 7 - \frac{3}{4} = 6\frac{4}{4} - \frac{3}{4} = 6\frac{1}{4}\]
\[\textbf{г)}\ 6 - 5\frac{5}{6} = 5\frac{6}{6} - 5\frac{5}{6} = \frac{1}{6}\]
\[\textbf{д)}\ 7 - 3\frac{7}{9} = 6\frac{9}{9} - 3\frac{7}{9} = 3\frac{2}{9}\]
\[\textbf{е)}\ 7 - 5\frac{4}{10} = 6\frac{10}{10} - 5\frac{4}{10} = 1\frac{6}{10}\]
\[\textbf{ж)}\ 1 - \frac{20}{30} = \frac{30}{30} - \frac{20}{30} = \frac{10}{30}\]
\[\textbf{з)}\ 1 - \frac{2}{7} = \frac{7}{7} - \frac{2}{7} = \frac{5}{7}\]
\[\boxed{\mathbf{8.}}\]
\[\textbf{а)}\ 5\frac{4}{7} + 8\frac{3}{7} = 13\frac{7}{7} = 14\]
\[\textbf{б)}\ 6\frac{2}{9} + 2\frac{8}{9} = 8\frac{10}{9} = 8 + 1\frac{1}{9} =\]
\[= 9\frac{1}{9}\]
\[\textbf{в)}\ 5\frac{7}{8} + 2\frac{3}{8} = 7\frac{10}{8} = 7 + 1\frac{2}{8} =\]
\[= 8\frac{2}{8}\]
\[\textbf{г)}\ 6\frac{8}{9} + \frac{4}{9} = 6\frac{12}{9} = 6 + 1\frac{3}{9} =\]
\[= 7\frac{3}{9}\]
\[\textbf{д)}\ 8\frac{6}{10} - 3\frac{7}{10} = 7\frac{16}{10} - 3\frac{7}{10} =\]
\[= 4\frac{9}{10}\]
\[\textbf{е)}\ 5\frac{8}{10} - 2\frac{9}{10} = 4\frac{18}{10} - 2\frac{9}{10} =\]
\[= 2\frac{9}{10}\]
\[\textbf{ж)}\ 7\frac{5}{8} + 3\frac{4}{8} = 10\frac{9}{8} = 11\frac{1}{8}\]
\[\textbf{з)}\ 9\frac{3}{14} - 7\frac{5}{14} = 8\frac{17}{14} - 7\frac{5}{14} =\]
\[= 1\frac{12}{14}\]
\[\textbf{и)}\ 2\frac{2}{5} + 3\frac{3}{5} = 5\frac{5}{5} = 6\]
\[к)\ 4\frac{3}{7} - 2\frac{3}{7} = 2\]
\[\boxed{\mathbf{9.}}\]
\[\textbf{а)}\ 1\frac{2}{7} + x = 2\]
\[x = 2 - 1\frac{2}{7}\]
\[x = 1\frac{7}{7} - 1\frac{2}{7}\]
\[x = \frac{5}{7}.\]
\[\textbf{б)}\ y + 3\frac{2}{5} = 6\frac{3}{5}\]
\[y = 6\frac{3}{5} - 3\frac{2}{5}\]
\[y = 3\frac{1}{5}.\]
\[\textbf{в)}\ 3\frac{3}{10} - x = 2\frac{7}{10}\]
\[x = 3\frac{3}{10} - 2\frac{7}{10}\]
\[x = 2\frac{13}{10} - 2\frac{7}{10}\]
\[x = \frac{6}{10}.\]
\[\textbf{г)}\ y - 7\frac{2}{10} = 1\frac{7}{10}\]
\[y = 1\frac{7}{10} + 7\frac{2}{10}\]
\[y = 8\frac{9}{10}.\]