Вычислите, используя законы сложения:
а) $\frac{1}{27} + \frac{5}{9} + \frac{1}{3}$;
б) $\frac{2}{9} + \frac{5}{6} + \frac{1}{18}$;
в) $\frac{2}{15} + \frac{1}{5} + \frac{3}{10}$;
г) $\frac{3}{8} + \frac{5}{12} + \frac{1}{24}$;
д) $\frac{1}{4} + \frac{3}{8} + \frac{5}{16}$;
е) $\frac{5}{7} + \frac{3}{14} + \frac{1}{21}$.
$\frac{1}{27} + \frac{5}{9} + \frac{1}{3} = \frac{1 + 15 + 9}{27} = \frac{15 + (1 + 9)}{27} = \frac{15 + 10}{27} = \frac{25}{27}$
$\frac{2}{9} + \frac{5}{6} + \frac{1}{18} = \frac{4 + 15 + 1}{18} = \frac{(4 + 1) + 15}{18} = \frac{5 + 15}{18} = \frac{20}{18} = \frac{10 * 2}{9 * 2} = \frac{10}{9}$
$\frac{2}{15} + \frac{1}{5} + \frac{3}{10} = \frac{4 + 6 + 9}{30} = \frac{(4 + 6) + 9}{30} = \frac{10 + 9}{30} = \frac{19}{30}$
$\frac{3}{8} + \frac{5}{12} + \frac{1}{24} = \frac{9 + 10 + 1}{24} = \frac{(9 + 1) + 10}{24} = \frac{10 + 10}{24} = \frac{20}{24} = \frac{5 * 4}{6 * 4} = \frac{5}{6}$
$\frac{1}{4} + \frac{3}{8} + \frac{5}{16} = \frac{4 + 6 + 5}{16} = \frac{(4 + 6) + 5}{16} = \frac{10 + 5}{16} = \frac{15}{16}$
$\frac{5}{7} + \frac{3}{14} + \frac{1}{21} = \frac{30 + 9 + 2}{42} = \frac{41}{42}$
Пожауйста, оцените решение
