x-1/4+1/3=1/2解：x=1/2+1/4-1/3 x=6/12+3/12-4/12 x=5/12
X－四分之一加三分之一等于二分之一X - 1/4 + 1/3 = 1/2X = 1/2 + 1/4 - 1/3 =3/4-1/3 =5/12
