（1）（3/5-3/5÷3）×3/2 =(3/5)(1-1/3)*3/2 =(3/5)[(2/3)*(3/2)] =(3/5)*1 =3/5 （2）2/21÷[3/7×（5/6-7/9）] =2/21÷[3/7×（1/18）]=2/21÷(1/42)=2/21*42=2*2=4
