№3. Вычислить: а) \(\frac{1}{6} + \frac{2}{7}\); б) \(\frac{11}{18} - \frac{5}{12}\); в) \(4\frac{7}{12} + 1\frac{3}{16}\); г) \(8\frac{17}{20} - 6\frac{7}{10}\)

а) \(\frac{1}{6} + \frac{2}{7}\) = \(\frac{1 \cdot 7 + 2 \cdot 6}{42}\) = \(\frac{7 + 12}{42}\) = \(\frac{19}{42}\) б) \(\frac{11}{18} - \(\frac{5}{12}\) = \(\frac{11 \cdot 2 - 5 \cdot 3}{36}\) = \(\frac{22 - 15}{36}\) = \(\frac{7}{36}\) в) \(4\frac{7}{12} + 1\frac{3}{16}\) = \(4 + \frac{7}{12} + 1 + \frac{3}{16}\) = \(5 + \frac{7 \cdot 4 + 3 \cdot 3}{48}\) = \(5 + \frac{28 + 9}{48}\) = \(5 + \frac{37}{48}\) = \(5\frac{37}{48}\) г) \(8\frac{17}{20} - 6\frac{7}{10}\) = \(8 + \frac{17}{20} - 6 - \frac{7}{10}\) = \(2 + \frac{17 - 7 \cdot 2}{20}\) = \(2 + \frac{17 - 14}{20}\) = \(2 + \frac{3}{20}\) = \(2\frac{3}{20}\) Ответ: а) \(\frac{19}{42}\); б) \(\frac{7}{36}\); в) \(5\frac{37}{48}\); г) \(2\frac{3}{20}\)