1、3.75*4又3/7-3又3/4*3又3/7 =3.75*(4+3/7-3-3/7) =3.75*1 =3.75 2、(11又5/6-2又1/4-5又1/2)除1又1/8 =(11-2-5)x8/9-(5/6-1/4-1/2)x8/9 =4x8/9-1/6x8/9 =32/9-4/27 =60/27 =20/9