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

设A=0.23+0.34,B=0.23+0.34+0.65

原式
=(1+A)×B-(1+B)×A
=B+AB-A-AB
=B-A
=0.23+0.34+0.65-0.23-0.34
=0.65

=(1+0.23+0.34)x(0.23+0.34)+(1+0.23+0.34)x0.65-(1+0.23+0.34)x(0.23+0.24)
-0.65x(0.23+0.34)
=0.65+(0.23+0.34)x0.65-0.65x(0.23+0.34)
=0.65

希望能帮你忙,不懂请追问,懂了请采纳,谢谢

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