57*55/56+27*27/28的简便算法.

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57*55/56+27*27/28的简便算法.
57*55/56+27*27/28的简便算法.

57*55/56+27*27/28的简便算法.
57*55/56+27*27/28
=[56+1]*55/56+(28-1)27/28
=56*55/56+55/56+28*27/28-27/28
=55+55/56+27-27/28
=82+1/56
=82又1/56

57*55/56+27*27/28
=(56+1)*55/56+(28-1)*27/28
=56*55/56+1*55/56+28*27/28-1*27/28
=55+55/56+27-27/28
=82+55/56-54/56
=82+1/56
=82又56分之1

57*55/56+27*27/28
=(56+1)(56-1)/56+(28-1)^2/28
=(56^2-1)/56+(28^2-2*28+1)/28
=56-1/56+28-2+1/28
=4593/56

57*55/56+27*27/28=(57*55+27*54)/56=((57+27)*54+57)/56
=84*54/56+57/56=81+57/56
=82+(1/56)