3又4分之3-（0.75+2又2分之1) =3+3/4-(0.75+2+1/2) =3+3/4-(3/4+2+1/2) =1/2 2又10分之7-1又7分之3+2.3= =2+7/10-1-3/7+2+3/10 =4-3/7 =3又4/7 =25/7
