Question

求解(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)=？奥数

Answer 1

(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23)*(0.12+0.23)-0.34*(0.12+0.23)
=(1+0.12+0.23)*[(0.12+0.23+0.34)-(0.12+0.23)]-0.34*(0.12+0.23)
=(1+0.12+0.23)*0.34-0.34*(0.12+0.23)
=[(1+0.12+0.23)--(0.12+0.23)]*0.34
=1*0.34
=0.34

追问

为什么要这样啊

追答

你不想这样也行呀
(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=1.35*0.69-1.69*0.35
=0.9315-0.5915
=0.34

Answer 2

(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=(1+0.12+0.23)*(0.12+0.23+0.34)-[1+(0.12+0.23+0.34)]*(0.12+0.23)
=(1+0.12+0.23)*(0.12+0.23+0.34)-1*(0.12+0.23)-(0.12+0.23+0.34) *(0.12+0.23)
=(0.12+0.23+0.34)*[(1+0.12+0.23)-(0.12+0.23)]-1*(0.12+0.23)
=(0.12+0.23+0.34)*1-1*(0.12+0.23)
=0.12+0.23+0.34-0.12-0.23
=0.34

追问

为什么

追答

(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=(1+0.12+0.23)*(0.12+0.23+0.34)-[1+(0.12+0.23+0.34)]*(0.12+0.23)
把 (0.12+0.23+0.34)看作整体，再用乘法分配律！
=(1+0.12+0.23)*(0.12+0.23+0.34)-1*(0.12+0.23)-(0.12+0.23+0.34) *(0.12+0.23)
去括号后，加号变减号！
=(0.12+0.23+0.34)*[(1+0.12+0.23)-(0.12+0.23)]-1*(0.12+0.23)
把 (0.12+0.23+0.34) 看作公因数， 用乘法分配律 ！
=(0.12+0.23+0.34)*1-1*(0.12+0.23)
中括号内结果是1
=0.12+0.23+0.34-0.12-0.23
=0.34

Answer 3

(1+0.12+0.23)*(0.12+0.23+0.34)-(1+0.12+0.23+0.34)*(0.12+0.23)
=(1+0.35)*(0.35+0.34)-(0.35+1.34)(0.35)
=0.35²+1.34*0.35+0.34-0.35²-1.34*0.35
=0.34