作业帮7.85×99+78.5×0.1简便计算.
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/30 00:50:52
7.85×99+78.5×0.1简便计算.
7.85×99+78.5×0.1简便计算.
7.85×99+78.5×0.1简便计算.
7.85×99+78.5×0.1
=78.5x9.9+78.5x0.1
=78.5x（9.9+0.1）
=78.5x10
=785
换算成78,5×!9,9＋0,1!
7.85*99+78.5*0.1=
7.85*99+7.85*1=
7.85*100=
785
＝7·85X（99十1）＝785
7.85×100
7.85×99+7.85×1
785！
用乘法分配律，原式=7.85×99+7.85×1=7.85×（99+1）=7.85×100=785，关键在于要把78.5×0.1化成7.85×1
78.5×9.9+78.5×0.1=78.5×（9.9+0.1）=78.5×10=785
=7.85×100-7.85+78.5×1÷10
=785-7.85+7,85
=785