(1+0.23+0.34)×(0.23+0.34+0.65)-(1+0.23+0.65)×(0.23+0.34)的巧算

问题描述:

(1+0.23+0.34)×(0.23+0.34+0.65)-(1+0.23+0.65)×(0.23+0.34)的巧算

(1+0.23+0.34)×(0.23+0.34+0.65)-(1+0.23+0.65)×(0.23+0.34)=(1+0.57)×(0.65+0.57)-0.57-0.23×0.57-0.65×0.57=1×(0.65+0.57)+0.57×(0.65+0.57)-0.57-0.23×0.57-0.65×0.57=0.65+0.57+0.57×0.65+0.57...