199点八乘六加九点九九乘八十简便计算

问题描述:

199点八乘六加九点九九乘八十简便计算

199.8×6+9.99×80
=(200-0.2)×6+(10-0.01)×80
=200×6-0.2×6+10×80-0.01×80
=120-1.2+800-0.8
=120+800-1.2-0.8
=920-2
=918