П.17 Выполните действие: a) $$\frac{1}{3} + \frac{1}{2}$$; б) $$\frac{2}{5} + \frac{3}{10}$$; в) $$\frac{7}{8} - \frac{3}{16}$$; г) $$\frac{11}{12} - \frac{3}{4}$$; д) $$\frac{4}{15} + \frac{3}{12}$$; е) $$\frac{2}{9} + \frac{11}{15}$$

a) $$\frac{1}{3} + \frac{1}{2} = \frac{2}{6} + \frac{3}{6} = \frac{5}{6}$$ б) $$\frac{2}{5} + \frac{3}{10} = \frac{4}{10} + \frac{3}{10} = \frac{7}{10}$$ в) $$\frac{7}{8} - \frac{3}{16} = \frac{14}{16} - \frac{3}{16} = \frac{11}{16}$$ г) $$\frac{11}{12} - \frac{3}{4} = \frac{11}{12} - \frac{9}{12} = \frac{2}{12} = \frac{1}{6}$$ д) $$\frac{4}{15} + \frac{3}{12} = \frac{16}{60} + \frac{15}{60} = \frac{31}{60}$$ е) $$\frac{2}{9} + \frac{11}{15} = \frac{10}{45} + \frac{33}{45} = \frac{43}{45}$$