1) 1 7/12/(3/8+5/12) 2)17/36/(3/8+5/12) 3) (3/14+5/7)/3 5/7 4) 19/24/(3/16+5/24)

1) 1 7/12/(3/8+5/12) =  19/12: (18/48+20/48) = 19/12: 38/48 = 19/12*48/38 =2 2) 17/36/(3/8+5/12)  = 17/36:  (18/48+20/48) = 17/36: 3848 = 17/36*48/38 =  34/57 3) (3/14+5/7)/3 5/7  = (3/14+10/14): 26/7 =13/14: 26/7 = 13/14*7/26 = 1/4 = 0,25  4) 19/24/(3/16+5/24) = 19/24: 19/48 =  19/24*48/19 =  2