Вычислите значение выражения наиболее удобным способом:
1) $\frac{3}{7} + \frac{14}{19} + \frac{4}{7} + \frac{5}{19}$;
2) $\frac{7}{16} + \frac{11}{42} + \frac{9}{16} + \frac{17}{42}$;
3) $\frac{5}{18} + \frac{4}{81} + \frac{7}{18} + \frac{5}{81}$;
4) $\frac{9}{40} + \frac{13}{50} + \frac{12}{50} + \frac{11}{40}$;
5) $3\frac{5}{11} + 1\frac{3}{16} + 2\frac{5}{16} + 4\frac{6}{11}$;
6) $1\frac{17}{24} + 3\frac{1}{36} + 5\frac{4}{24} + 2\frac{8}{36}$.
$\frac{3}{7} + \frac{14}{19} + \frac{4}{7} + \frac{5}{19} = (\frac{3}{7} + \frac{4}{7}) + (\frac{14}{19} + \frac{5}{19}) = \frac{7}{7} + \frac{19}{19} = 1 + 1 = 2$
$\frac{7}{16} + \frac{11}{42} + \frac{9}{16} + \frac{17}{42} = (\frac{7}{16} + \frac{9}{16}) + (\frac{11}{42} + + \frac{17}{42}) = \frac{16}{16} + \frac{28}{42} = 1\frac{2}{3}$
$\frac{5}{18} + \frac{4}{81} + \frac{7}{18} + \frac{5}{81} = (\frac{5}{18} + \frac{7}{18}) + (\frac{4}{81} + \frac{5}{81}) = \frac{12}{18} + \frac{9}{81} = \frac{2}{3} + \frac{1}{9} = \frac{6}{9} + \frac{1}{9} = \frac{7}{9}$
$\frac{9}{40} + \frac{13}{50} + \frac{12}{50} + \frac{11}{40} = (\frac{9}{40} + \frac{11}{40}) + (\frac{13}{50} + \frac{12}{50}) = \frac{20}{40} + \frac{25}{50} = \frac{1}{2} + \frac{1}{2} = 1$
$3\frac{5}{11} + 1\frac{3}{16} + 2\frac{5}{16} + 4\frac{6}{11} = (3\frac{5}{11} + 4\frac{6}{11}) + (1\frac{3}{16} + 2\frac{5}{16}) = 8 + 3\frac{8}{16} = 11\frac{1}{2}$
$1\frac{17}{24} + 3\frac{1}{36} + 5\frac{4}{24} + 2\frac{8}{36} = (1\frac{17}{24} + 5\frac{4}{24}) + (3\frac{1}{36} + 2\frac{8}{36}) = 6\frac{21}{24} + 5\frac{9}{36} = 6\frac{7}{8} + 5\frac{2}{8} = 12\frac{1}{8}$
Пожауйста, оцените решение
