Question

78.5乘0.81加7.85乘1.19简便计算？

Answer 1

① 78.5×0.81+7.85×1.19
=78.5×0.81+7.85（2-0.81）
=78.5×0.81+15.7-7.85×0.81
=0.81×（78.5-7.85）+15.7
=0.81×70.65+15.7
=（1-0.2+0.01）×70.65+15.7
=70.65-14.13+0.7065+15.7
=56.52+0.7065+15.7
=57.2265+15.7
=72.9265
②78.5×0.81+7.85×1.19
=785×0.081+785×0.0119
=785×（0.081+0.0119）
=785×0.0929
=72.9265

Answer 2

78.5×0.81+7.85×1.19=72.9265

Answer 3

78.5*0.81+7.85*11.9
=78.5*(0.81+1.19)
=78.5*2
=157
乘法分配律来简便算法

Answer 4

78.5×0.81+7.85×1.19
=7.85（8.1+1.19）
=7.85×9.29
=72.9265