125/147*21/50-70/119*17/210-3/14*7/9 помогите решить

$\frac{125}{147} \times \frac{21}{50} = \frac{5}{7 \times 2} = \frac{5}{14}$
$\frac{70}{119} \times \frac{17}{210} = \frac{1}{21}$
$\frac{3}{14} \times \frac{7}{9} = \frac{1}{6}$
$\frac{5}{14} - \frac{1}{21} = \frac{15}{42} - \frac{2}{42} = \frac{13}{42}$
$\frac{13}{42} - \frac{1}{6} = \frac{13}{42} - \frac{7}{42} = \frac{6}{42} = \frac{1}{7}$
Ответ:
$\frac{1}{7}$