请采纳
5/12-1/4＋1/3=5/12-3/12＋4/12=（5-3+4）/12=6/12=1/2这个数是1/2。
x-1/3+1/4=5/12x-(1/3-1/4)=5/12x-1/12=5/12x=1/22分之1
