1) 12 3/8 + 8 1/6

### Умножение дробей 1) $\frac{5}{6} \cdot \frac{3}{20} = \frac{5 \cdot 3}{6 \cdot 20} = \frac{15}{120} = \frac{1}{8}$ 2) $\frac{3}{7} \cdot \frac{6}{11} = \frac{3 \cdot 6}{7 \cdot 11} = \frac{18}{77}$ 3) $\frac{10}{11} \cdot \frac{11}{26} = \frac{10 \cdot 11}{11 \cdot 26} = \frac{10}{26} = \frac{5}{13}$ 4) $\frac{24}{65} \cdot \frac{39}{40} = \frac{24 \cdot 39}{65 \cdot 40} = \frac{3 \cdot 3}{5 \cdot 5} = \frac{9}{25}$ ### Действия с дробями (сложение и вычитание) 1) $12\frac{3}{8} + 8\frac{1}{6} = 12 + 8 + \frac{9}{24} + \frac{4}{24} = 20\frac{13}{24}$ 2) $7\frac{5}{6} - 3\frac{2}{3} = 7\frac{5}{6} - 3\frac{4}{6} = 4\frac{1}{6}$ 3) $8\frac{5}{12} - 6\frac{7}{20} = 8\frac{25}{60} - 6\frac{21}{60} = 2\frac{4}{60} = 2\frac{1}{15}$ 4) $3\frac{1}{16} - 1\frac{1}{8} = 3\frac{1}{16} - 1\frac{2}{16} = 2\frac{17}{16} - 1\frac{2}{16} = 1\frac{15}{16}$ 5) $7\frac{9}{20} - 5\frac{17}{30} = 7\frac{27}{60} - 5\frac{34}{60} = 6\frac{87}{60} - 5\frac{34}{60} = 1\frac{53}{60}$