21x33十21x43十79x76
=21x（33+43）+79x76
=21x76+79x76
=（21+79）x76
=100x76
=7600
谢谢，请采纳
21X33十21x43十79x76
=21×（33+43）+79×76
=21×76+79×76
=（21+79）×76
=100×76
=7600
是这样的楼主
5,99x79+21x3,99
=3,99x79+2X79+21x3,99
=3,99x79+21x3,99+2X79
=3,99x（79+21）+2X79
=3.99X100+2X79
=399+158
=399+1+157
=400+157
=557 楼主做这题目时 发现不可以用分配律 这时强行吧它换成可以分配的
凑成一样的数出现 （叫做霸王硬上弓）
打的比较细 所以比较长 楼主做的时候大可省掉些东西
如果可以望楼主采纳
21x44十79x52十8x21
=21x44十8x21十79x52
=21x（44十8）十79x52
=21x52十79x52
=（21+79）x52
=100x52
=5200
79x79-79 +21x7
=79×（79-1）+21×7
=79×78+21×7
=6162-147
=6015
这道题没有简便方法
如果是这样，就可以简便
79x79-79+22x79
=（79-1+22）x79
=（78+22）x79
=100x79
=7900
246x79-25x79一21x79的简便方法
246x79-25x79一21x79
=79*（246-25-21）
=79*200
=15800
21x36+21x75-21x11
=21x（36+75-11）
=21x100
=2100
21x21十21x78十21
=21(21+78+1)
=21*100
=2100
250×79×43=250×（80-1）（40+3）=(20000-250)(40+3)=19750*40+19750*3=790000+59250=849250
=21X(44+8) +79X52
=21X52+79X52
=52X(21+79)
=52X100
=5200