(8 3/4 - 7 8/6) - 4,8 + 3 3/5 = -47/60,
1) 8 3/4 - 7 8/6 = (8 - 7) + (3/4 - 8/6) = 1 + (9/12 - 16/12) = 1 - 7/12 = 5/12,
2) 5/12 - 4,8 = 5/12 - 48/10 = 25/60 - 288/60 = -263/60 = - 4 23/60,
3) -4 23/60 + 3 3/5 = -263/60 + 18/5 = -263/60 + 216/60 = -47/60