2/3-3/8+1/3-5/8
=(2/3+1/3)-(3/8+5/8)
=1-1
=0
用交换律和结合律简算原式＝2／3+1／3-（3／8+5／8）＝1-1＝0
简便计算2/3-3/8+1/3-5/8=（2/3+1/3）-（3/8+5/8）=1-1=0
