3. Выполните действия: a) $$\frac{7}{8} - \frac{5}{8}$$ б) $$\frac{13}{16} + \frac{7}{16}$$ в) $$\frac{5}{8} + \frac{4}{8}$$ г) $$1\frac{3}{8} - \frac{7}{8}$$ д) $$4\frac{2}{5} + 3\frac{3}{5}$$ е) $$2\frac{3}{4} - 1\frac{5}{4}$$ ж) $$4\frac{2}{3} - 1\frac{2}{3}$$ з) $$3\frac{1}{5} - 2\frac{2}{5}$$

a) $$\frac{7}{8} - \frac{5}{8} = \frac{7-5}{8} = \frac{2}{8} = \frac{1}{4}$$ б) $$\frac{13}{16} + \frac{7}{16} = \frac{13+7}{16} = \frac{20}{16} = \frac{5}{4} = 1\frac{1}{4}$$ в) $$\frac{5}{8} + \frac{4}{8} = \frac{5+4}{8} = \frac{9}{8} = 1\frac{1}{8}$$ г) $$1\frac{3}{8} - \frac{7}{8} = \frac{11}{8} - \frac{7}{8} = \frac{11-7}{8} = \frac{4}{8} = \frac{1}{2}$$ д) $$4\frac{2}{5} + 3\frac{3}{5} = (4+3) + (\frac{2}{5} + \frac{3}{5}) = 7 + \frac{5}{5} = 7 + 1 = 8$$ е) $$2\frac{3}{4} - 1\frac{5}{4} = \frac{11}{4} - \frac{9}{4} = \frac{11-9}{4} = \frac{2}{4} = \frac{1}{2}$$ ж) $$4\frac{2}{3} - 1\frac{2}{3} = (4-1) + (\frac{2}{3} - \frac{2}{3}) = 3 + 0 = 3$$ з) $$3\frac{1}{5} - 2\frac{2}{5} = \frac{16}{5} - \frac{12}{5} = \frac{4}{5}$$