5/6*9/15-5/12*4/15 7/18*9/14+1/3*6/7 9/20*2/3+5/14*7/25 3 целых 3/4*2/5-3 целых 6/25*5/27

$1) \frac{5}{6} * \frac{9}{15}- \frac{5}{12}* \frac{4}{15}= \frac{3}{10}- \frac{1}{9} = \frac{27-10}{90}= \frac{17}{90}$
$2) \frac{7}{18}* \frac{9}{14} + \frac{1}{3} * \frac{6}{7} = \frac{1}{4} + \frac{3}{7} = \frac{17}{28} [tex]3) \frac{9}{20}* \frac{2}{3} + \frac{5}{14} * \frac{7}{25} = \frac{3}{10} + \frac{1}{10}= \frac{2}{5}$
$4) 3 \frac{3}{4} * \frac{2}{5} -3 \frac{6}{25} * \frac{5}{27} = \frac{15*2}{4*5} - \frac{81*5}{25*27} = \frac{3}{2} - \frac{3}{5} = \frac{9}{10}$