A) 6/7 + (2/11 - 6/7). b) 83/5 . (-1/3) - 68/5 . (-1/3) + 3/4

a) 6/7+(2/11-6/7)
b) 83/5.(-1/3) - 68/5.(-1/3)+3/4
c) 5/8+(6/11-5/8)
d) 3/7.(3/2-0,5) : (-3)^2