Вычислите 7/15-3/10 5/42:6/7 0,4+2/3 36:1 2/7-19,8+2 5/6

Решите задачу:

$\frac{7}{15} - \frac{3}{10} = \frac{14-9}{30} = \frac{5}{30} = \frac{1}{6}$

$\frac{5}{42} : \frac{6}{7} = \frac{5}{42} * \frac{7}{6} = \frac{5}{6*6} = \frac{5}{36}$

$\frac{2}{5} + \frac{2}{3} = \frac{6+10}{15} = \frac{16}{15}$

$36 : \frac{9}{7} -19,8+ \frac{17}{6} =36* \frac{7}{9} -19,8+ \frac{17}{6} = 4*7-19,8+ \frac{17}{6} =$ $28-19,8+ \frac{17}{6} =8,2+ \frac{17}{6} = \frac{82}{10} + \frac{17}{6} = \frac{41}{5} + \frac{17}{6} = \frac{246+85}{30} = \frac{331}{30}$