4+2/3-1+11/12-3/4 (这里打不分数,所以加号为又)
=14/3-23/12-3/4 (寻找3 12 4的最小公倍数,为12)
=56/12-23/12-9/12 (56/12为14*4/3*4,以此类推)
=(56-23-9)/12
=24/12 (进行化简)
=2