ccpaging 2013-1-15 19:26
回复 1楼伊伊yiyi 的帖子
4+9=13
177+23=200.
junhuayang2005 2013-1-15 21:22
[quote]原帖由 [i]伊伊yiyi[/i] 于 2013-1-15 19:03 发表 [url=http://ww123.net/redirect.php?goto=findpost&pid=9158982&ptid=4836934][img]http://ww123.net/images/common/back.gif[/img][/url]
4*177+177*9+23*13 [/quote]
乘法分配律的逆用.
quqinglei 2013-1-16 11:12
4*177+177*9+23*13
=(4+9)*177+23*13
=13*177+23*13
=(177+23)*13
=200*13
=2600.