A) -43-39+43-51=-90
Б) 86-34-56+24 = (86+24) - (34+56) = 110 - 90 = 20
В) -4/25 + (-7/33) - (-26/33) = -4/25 + (-7/33 + 26/33) = -4/25 + 19/33 = -132/825 + + 475/825 = 343/825
Г) -8/33 + (-7/33) - (-26/33) = -8/33 - 7/33 + 26/33 = -15/33 + 26/33= 11/33