(2 13/48+2 5/12):3 3/4-9 3/4:12=
(2 13/48+2 5/12):3 3/4-9 3/4:12= (109/48 + 29/12) : 15/4 - 39/4 : 12 = = 225/48 : 15/4 - 39/48 = 15/12 - 13/16 = (20 - 13) / 16 = 7 / 16 = 0,4375