Выполните действие:
а) $\frac{1}{4} + \frac{1}{5}$;
б) $\frac{1}{3} + \frac{1}{7}$;
в) $\frac{3}{5} + \frac{3}{4}$;
г) $\frac{1}{2} + \frac{7}{9}$;
д) $\frac{5}{7} + 0$;
е) $\frac{2}{3} - \frac{2}{5}$;
ж) $\frac{1}{2} - \frac{1}{3}$;
з) $\frac{3}{5} - \frac{4}{7}$;
и) $\frac{5}{7} - \frac{1}{6}$;
к) $\frac{8}{9} - 0$;
л) $\frac{3}{4} + \frac{4}{5}$;
м) $\frac{3}{4} + \frac{2}{9}$.
$\frac{1}{4} + \frac{1}{5} = \frac{5}{20} + \frac{4}{20} = \frac{9}{20}$
$\frac{1}{3} + \frac{1}{7} = \frac{7}{21} + \frac{3}{21} = \frac{10}{21}$
$\frac{3}{5} + \frac{3}{4} = \frac{12}{20} + \frac{15}{20} = \frac{27}{20} = 1\frac{7}{20}$
$\frac{1}{2} + \frac{7}{9} = \frac{9}{18} + \frac{14}{18} = \frac{23}{18} = 1\frac{5}{18}$
$\frac{5}{7} + 0 = \frac{5}{7}$
$\frac{2}{3} - \frac{2}{5} = \frac{10}{15} - \frac{6}{15} = \frac{4}{15}$
$\frac{1}{2} - \frac{1}{3} = \frac{3}{6} - \frac{2}{6} = \frac{1}{6}$
$\frac{3}{5} - \frac{4}{7} = \frac{21}{35} - \frac{20}{35} = \frac{1}{35}$
$\frac{5}{7} - \frac{1}{6} = \frac{30}{42} - \frac{7}{42} = \frac{23}{42}$
$\frac{8}{9} - 0 = \frac{8}{9}$
$\frac{3}{4} + \frac{4}{5} = \frac{15}{20} + \frac{16}{20} = \frac{31}{20} = 1\frac{11}{20}$
$\frac{3}{4} + \frac{2}{9} = \frac{27}{36} + \frac{8}{36} = \frac{35}{36}$
Пожауйста, оцените решение