Разбираемся:
а) |-5,6| : |-28| = 5,6 : 28 = 0,2
б) |-1 5/6| * |6 6/11| = (1 5/6) * (6 6/11) = (11/6) * (72/11) = 72/6 = 12
в) |9,5| + |-2 6/11| = 9,5 + 2 6/11 = 9,5 + 2,5454... = 12,0454...