\[\boxed{Страница\ 27.}\]
\[\boxed{\mathbf{1.}}\]
\[1.\]
\[\textbf{а)}\ 3 - 1\frac{6}{8} = 2\frac{8}{8} - 1\frac{6}{8} = 1\frac{2}{8}\]
\[\textbf{б)}\ 2\frac{1}{4} - 1\frac{3}{4} = 1\frac{5}{4} - 1\frac{3}{4} = \frac{2}{4}\]
\[2.\]
\[1 - \frac{7}{15} = \frac{15}{15} - \frac{7}{15} = \frac{8}{15}\]
\[4 - 2\frac{5}{8} = 3\frac{8}{8} - 2\frac{5}{8} = 1\frac{3}{8}\]
\[5\frac{2}{9} - \frac{4}{9} = 4\frac{11}{9} - \frac{4}{9} = 4\frac{7}{9}\]
\[8\frac{1}{11} - 4\frac{5}{11} = 7\frac{12}{11} - 4\frac{5}{11} = 3\frac{7}{11}\]
\[3.\]
\[1 - вся\ площадь\ сада.\]
\[1)\ 1 - \left( \frac{5}{12} + \frac{2}{12} + \frac{4}{12} \right) =\]
\[= 1 - \frac{11}{12} = \frac{12}{12} - \frac{11}{12} =\]
\[= \frac{1}{12}\ (часть) - площади\ сада\]
\[занимают\ сливы.\]
\[2)\ 12 \cdot 12 = 144\ \left( м^{2} \right) - площадь\ \]
\[всего\ сада.\]
\[Ответ:144\ м^{2}\text{.\ }\]
\[\boxed{\mathbf{2.}}\]
\[1.\]
\[\textbf{а)}\ 4 - 1\frac{5}{6} = 3\frac{6}{6} - 1\frac{5}{6} = 2\frac{1}{6}\]
\[\textbf{б)}\ 3\frac{1}{4} - 2\frac{3}{4} = 2\frac{5}{4} - 2\frac{3}{4} = \frac{2}{4}\]
\[2.\ \]
\[1 - \frac{5}{13} = \frac{13}{13} - \frac{5}{13} = \frac{8}{13}\]
\[5 - 3\frac{4}{7} = 4\frac{7}{7} - 3\frac{4}{7} = 1\frac{3}{7}\]
\[4\frac{2}{5} - \frac{3}{5} = 3\frac{7}{5} - \frac{3}{5} = 3\frac{4}{5}\]
\[9\frac{6}{10} - 2\frac{7}{10} = 8\frac{16}{10} - 2\frac{7}{10} = 6\frac{9}{10}\]
\[3.\]
\[1 - все\ пирожки.\]
\[1)\ 1 - \left( \frac{2}{15} + \frac{5}{15} + \frac{6}{15} \right) =\]
\[= \frac{15}{15} - \frac{13}{15} = \frac{2}{15}\ (часть) -\]
\[пирожки\ с\ вареньем.\]
\[2)\ 30\ :2 \cdot 15 = 15 \cdot 15 =\]
\[= 225\ (пирожков) - всего\ \]
\[привезли\ в\ школьный\ буфет.\]
\[Ответ:225\ пирожков.\]