Выполни сложение в номере а): 3/4 + 2/3

- a) $\frac{3}{4} + \frac{2}{3} = \frac{3 * 3}{4 * 3} + \frac{2 * 4}{3 * 4} = \frac{9}{12} + \frac{8}{12} = \frac{17}{12}$ - б) $\frac{4}{9} + \frac{1}{6} = \frac{4 * 2}{9 * 2} + \frac{1 * 3}{6 * 3} = \frac{8}{18} + \frac{3}{18} = \frac{11}{18}$ - в) $\frac{3}{10} + \frac{2}{15} = \frac{3 * 3}{10 * 3} + \frac{2 * 2}{15 * 2} = \frac{9}{30} + \frac{4}{30} = \frac{13}{30}$ - г) $\frac{7}{15} + \frac{3}{40} = \frac{7 * 8}{15 * 8} + \frac{3 * 3}{40 * 3} = \frac{56}{120} + \frac{9}{120} = \frac{65}{120} = \frac{13}{24}$ - д) $\frac{6}{7} + \frac{9}{21} = \frac{6 * 3}{7 * 3} + \frac{9}{21} = \frac{18}{21} + \frac{9}{21} = \frac{27}{21} = \frac{9}{7}$ - e) $\frac{11}{20} + \frac{6}{15} = \frac{11 * 3}{20 * 3} + \frac{6 * 4}{15 * 4} = \frac{33}{60} + \frac{24}{60} = \frac{57}{60} = \frac{19}{20}$