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(1+0.228-0.21)*(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)*(0.

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(1+0.228-0.21)*(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)*(0.228-0.21)巧算?
写清思路
(1+0.228-0.21)*(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)*(0.
若设0.228-0.21=0.018=x
则(1+0.228-0.21)*(0.228-0.21+0.2003)-(1+0.228-0.21+0.2003)*(0.228-0.21)
=(1+x)(x+0.2003)-(1.2003+x)*x
=x+0.2003+x方+0.2003x-1.2003x-x方
=0.2003