(1/6 +1/10 + 1/15):(1/6 + 1/30)...

Решите задачу:

$\frac{ (\frac{1}{6} +\frac{1}{10} + \frac{1}{15}):((\frac{1}{6} + \frac{1}{30})}{(\frac{1}{6} +\frac{1}{4} - \frac{1}{5}):(\frac{1}{4} - \frac{1}{6})} = \frac{25}{39}$
$1) \frac{1}{6} +\frac{1}{10} + \frac{1}{15} = \frac{5}{30} +\frac{3}{30} + \frac{2}{30} = \frac{10}{30} = \frac{1}{3}$
$2) \frac{1}{6} +\frac{1}{30} = \frac{5}{30} +\frac{1}{30} = \frac{6}{30} = \frac{1}{5}$
$3) \frac{1}{3} : \frac{1}{5} = \frac{5}{3}$
$4) \frac{1}{6} +\frac{1}{4} - \frac{1}{5} = \frac{10}{60} +\frac{15}{60} - \frac{12}{60} = \frac{13}{60}$
$5) \frac{1}{4} - \frac{1}{6} = \frac{6}{24} - \frac{4}{24} = \frac{2}{24} = \frac{1}{12}$
$6) \frac{13}{60} : \frac{1}{12} = \frac{13 * 12}{60} = \frac{13}{5}$
$7) \frac{\frac{5}{3}}{\frac{13}{5}} = \frac{5*5}{3*13} = \frac{25}{39}$