24x35=4x6x5x7
=4x5x6x7
=20x6x7
=120x7
=(100+20)x7
=100x7+20x7
=700+140
=840
先观察各个乘数,然后把24换成4x6,35换成5x7,利用乘法交换律,凑整
24乘35的简便方法
24*35=35*2*12=70*12=840
24x35=4x6x5x7
=4x5x6x7
=20x6x7
=120x7
=(100+20)x7
=100x7+20x7
=700+140
=840
先观察各个乘数,然后把24换成4x6,35换成5x7,利用乘法交换律,凑整
24乘35的简便方法
24*35=35*2*12=70*12=840