原式=3/4+7/2+2/3-(1/6+1)=9/12+42/12+8/12-(2/12+12/12)=59/12-14/12=45/12=15/4=3又3/4
解：原式=3/4+7/2-1/6+2/3+1 =17/4-1/6+2/3+1 =57/12+1 =69/12 (你题目的最后应该是减负一吧？)
