简便计算：(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34)

简便计算：(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34)
简便计算：(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34)

简便计算：(1+0.23+0.34)*(0.23+0.34+0.65)-(1+0.23+0.34+0.65)*(0.23+0.34)
令A=0.23+0.34=0.57
原式=(1+A)*(A+0.65)-(1+A+0.65)*A
=A+A2+0.65A+0.65-A-A2-0.65A
=0.65

后面用乘法分配律得到
(0.23+0.34+0.65)*(0.23+0.34)+(0.23+0.34)
和前面得到
(0.23+0.34+0.65)*[1+0.23+0.34-(0.23+0.34)]-(0.23+0.34)
等于0.65

设 1+0.23+0.34=A
A*（A-1+0.65）-（A+0.65）（A-1）
=A*（A+0.65）-A-[（A+0.65）*A-（A+0.65）}
=A*（A+0.65）-A-（A+0.65）*A+（A+0.65）
=0.65

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