子页,子页,子页,子页,子页题目,内容:,子页,子页,子页,子页,子页题目,内容:,子页,子页,子页,子页,子页题目,内容:,子页,子页,子页,子页,子页题目,内容:,内容:,子页题目,子页,子页,子页,子页,主页,子页,子页题目,子页,子页,子页,主页,子页,T,H,A,N,K,Y,O,U,*,北师大版 四年级上册 第四单元 运算律,第二课时,绿色圃中小学教育网,绿色圃中小学教育网,白沙小学 汪靖雯,(,4,8,),25=,(),25,(),25,练一练,4,8,254=,1258=,72,128=,99,201=,4125=,256-56=,100,200,1000,300,500,200,(,80,4,),25,1,.,观察下面算式的特点并计算。,8,(,125,9,),(,75,25,),31,8,(,125,9,),=8125,89,=1000,72,=1072,(,75,25,),31,=10031,=3100,3472,3428,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,28,34,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,.,72,34,72 34,+,28 34,28+72,=(28 +72 )34,