四升五年级数学简便计算练习题

四升五年级数学简便计算练习题


简介:
3.29+0.73+2.27    =3.29+(0.73+2.27) =3.29+3  =6.29   (加法结合律) 3.29-0.73-2.27        =3.29-(0.73+2.27) =3.29-3  =0.29 (减法的性质) 7.5+2.5-7.5+2.5 =(7.5-7.5)+(2.5+2.5) =0+5            =5 (同级运算交换)