乘法结合律,三个数相乘,先把前两个数相乘,在和另外一个数相乘,或先把后两个数相乘,再和另外一个数相乘,积不变。
字母表示: a×b×c=(a×b)×c或=a×(b×c)
40×25×35×20
=(40×25)×(35×20)
=1000×700
=700000
简便计算
40x25×35×20
=(40x25)x(35x20)
=1000x700
=700000
40X25X35X20
=(40X25)X(35X20)
=1000X700
=700000
=1000×700
=700000
简便计算过程方法如下
解:40x25×35×20
=(40x25)x(35x20)
=1000x700
=700000