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

[tex] \frac{5}{6}* \frac{3}{5}- \frac{5}{12}* \frac{4}{15}= \frac{15}{30} - \frac{20}{180} = \frac{1}{2}- \frac{1}{9} = \frac{7}{18} [/tex]