3. Вычислите: 1) 5/6 + 3/5; 2) 11/12 - 1/4; 3) 13/15 - 2/5

1) \(\frac{5}{6} + \frac{3}{5}\) * НОК(6, 5) = 30 * \(\frac{5}{6} = \frac{5 \cdot 5}{6 \cdot 5} = \frac{25}{30}\) * \(\frac{3}{5} = \frac{3 \cdot 6}{5 \cdot 6} = \frac{18}{30}\) * \(\frac{25}{30} + \frac{18}{30} = \frac{25 + 18}{30} = \frac{43}{30}\) 2) \(\frac{11}{12} - \frac{1}{4}\) * НОК(12, 4) = 12 * \(\frac{1}{4} = \frac{1 \cdot 3}{4 \cdot 3} = \frac{3}{12}\) * \(\frac{11}{12} - \frac{3}{12} = \frac{11 - 3}{12} = \frac{8}{12} = \frac{2}{3}\) 3) \(\frac{13}{15} - \frac{2}{5}\) * НОК(15, 5) = 15 * \(\frac{2}{5} = \frac{2 \cdot 3}{5 \cdot 3} = \frac{6}{15}\) * \(\frac{13}{15} - \frac{6}{15} = \frac{13 - 6}{15} = \frac{7}{15}\) **Ответ:** 1) 43/30 2) 2/3 3) 7/15