4/5+[7/8-4/5] 7/10-[2/15+1/6] 1-1/3-1/7 5/6+11/14 5/6-[4/9-1/3]谢谢了,

4/5+[7/8-4/5] = 4/5 + 7/8 - 4/5 = 7/8 7/10-[2/15+1/6] = 7/10 - 2/15 + 1/6 = 21/30 - 4/30 + 5/30 = 22/30 =11/15 1-1/3-1/7 = 1 - (1/3 + 1/7) = 1 - 10/21 = 11/21 5/6+11/14 = 35/42 + 33/42 = 68/42 = 34/21...