15*(1+1/3-1/5) = 15*1 + 15*1/3 - 15*1/5 = =15+5-3 = 17
48*(19/24 - 7/12 + 3/8) = 48*19/24 - 48*7/12 + 48*3/8 = 2*19-4*7+6*3=38-28+18=28
7/9 * (6/7 - 9/14) = (7*6)/(9*7) - (7*9)/(9*14) = 6/9 -7/14 = 2/3 - 1/2 = 4/6 - 3/6 = 1/6
(15/16 - 5/12 + 2 1/2) * 4/5 = (15*4)/(16*5) - (5*4)/(12*5) + (5*4)/(2*5) =
= 3/4 - 1/3 + 2 = 9/12 - 4/12 + 2 =
