Выполните сложение дробей: а) 1/3 + 1/6

1. Выполните сложение: а) $$\frac{1}{3} + \frac{1}{6} = \frac{2}{6} + \frac{1}{6} = \frac{3}{6} = \frac{1}{2}$$ б) $$\frac{3}{5} + \frac{2}{7} = \frac{3 \cdot 7}{5 \cdot 7} + \frac{2 \cdot 5}{7 \cdot 5} = \frac{21}{35} + \frac{10}{35} = \frac{31}{35}$$ в) $$\frac{5}{8} + \frac{1}{4} = \frac{5}{8} + \frac{1 \cdot 2}{4 \cdot 2} = \frac{5}{8} + \frac{2}{8} = \frac{7}{8}$$ г) $$\frac{1}{2} + \frac{1}{4} = \frac{1 \cdot 2}{2 \cdot 2} + \frac{1}{4} = \frac{2}{4} + \frac{1}{4} = \frac{3}{4}$$ д) $$\frac{2}{3} + \frac{3}{8} = \frac{2 \cdot 8}{3 \cdot 8} + \frac{3 \cdot 3}{8 \cdot 3} = \frac{16}{24} + \frac{9}{24} = \frac{25}{24} = 1\frac{1}{24}$$ е) $$\frac{4}{7} + \frac{1}{2} = \frac{4 \cdot 2}{7 \cdot 2} + \frac{1 \cdot 7}{2 \cdot 7} = \frac{8}{14} + \frac{7}{14} = \frac{15}{14} = 1\frac{1}{14}$$ 2. Выполните вычитание: а) $$\frac{7}{9} - \frac{1}{3} = \frac{7}{9} - \frac{1 \cdot 3}{3 \cdot 3} = \frac{7}{9} - \frac{3}{9} = \frac{4}{9}$$ б) $$\frac{5}{6} - \frac{2}{5} = \frac{5 \cdot 5}{6 \cdot 5} - \frac{2 \cdot 6}{5 \cdot 6} = \frac{25}{30} - \frac{12}{30} = \frac{13}{30}$$ в) $$\frac{3}{4} - \frac{1}{8} = \frac{3 \cdot 2}{4 \cdot 2} - \frac{1}{8} = \frac{6}{8} - \frac{1}{8} = \frac{5}{8}$$ г) $$\frac{5}{6} - \frac{1}{2} = \frac{5}{6} - \frac{1 \cdot 3}{2 \cdot 3} = \frac{5}{6} - \frac{3}{6} = \frac{2}{6} = \frac{1}{3}$$ д) $$\frac{7}{8} - \frac{3}{5} = \frac{7 \cdot 5}{8 \cdot 5} - \frac{3 \cdot 8}{5 \cdot 8} = \frac{35}{40} - \frac{24}{40} = \frac{11}{40}$$ е) $$\frac{9}{10} - \frac{1}{5} = \frac{9}{10} - \frac{1 \cdot 2}{5 \cdot 2} = \frac{9}{10} - \frac{2}{10} = \frac{7}{10}$$