56.5×9.9+56.5的巧算

分类: 作业答案 • 2021-12-20 04:11:06

问题描述：

56.5×9.9+56.5的巧算

答

56.5×10－5.65＋56.5
56.5×11－5.65

答

56.5×9.9+56.5
=56.5×(10-0.1)+56.5
=56.5×10-56.5×0.1+56.5
=565-5.65+56.5
=615.85

答

56.5×9.9+56.5
=56.5×（10-0.1）+56.5
=56.5×10-0.1×56.5+56.5
=565-5.65+56.5
=565+50.85
=615.85