北师大版四年级下册小数简便运算(共3页).doc

北师大版小学四年级下册小数简便运算1.加法交换结合律：4.80.251.75= 57.81.432.20.57= 1.288.90.72= 3.572.881.43= 3.785.270.73= 1.292.351.711.65= 16.728.93.3= 15.839.510.5= 8.221.970.78= 0.580.390.420.61= 1.250.753.20= 1.530.381.62=7.53.412.536.6= 1.630.321.372.68=2.乘法交换结合律（一）：（152.5）4= 382.54=