四年级上册运算律练习题

加法父换律和结合律1\基本题：38+169+162a+b+c二b+a+c(a+b)+c二a+(b+c)256+168+144+32377+569+123+312\a-b~c=a~(b+c)a-(b+c)=a-b~c652-67-133789-152-2488941-386-6141597-(597+650)3651-(123+651)256-(32+56)二、乘法交换律和结合律1x基本题：aXb=bXa(aXb)Xc=aX(bXc)25X17X4125X57X8125X25X4X850X89X22、变化题：例：25X44=25X4X11125X25X32125X8825X16150X18三、乘法分配律1基本题：：（a+b）Xc二aXc+bXc(a~b)Xc二aXc-bXc18X26+18X7468X57+32X5797X31-87X31157X69-57X69(25+6)X4(125+25)X8(80-8)X125(100-2)X2699X87+872、变化题(1):例：72X99=72X(100-1)=72X100-72X1101X86=(100+1)X86=100X86+1X8689X9938X9875X9945X98102X85101X72103X13101X993、变化题⑵：例：23X98+46=23X98+23X2=23X(98+2)13X97+3945X98+902X56+6X284、67X21+18X21+85X7939X56+39X45-39