来自高长艳的问题
简便计算几道.(80+1/78)×79(224+1/222)×1/2231/2+1/6+1/12+……1/90
简便计算几道.
(80+1/78)×79
(224+1/222)×1/223
1/2+1/6+1/12+……1/90
1回答
2020-10-09 10:42
简便计算几道.(80+1/78)×79(224+1/222)×1/2231/2+1/6+1/12+……1/90
简便计算几道.
(80+1/78)×79
(224+1/222)×1/223
1/2+1/6+1/12+……1/90
(80+1/78)×79=80X79+1/78x79=80X(80-1)+1/78X(78+1)=80X80-80X1+1/78X78+1/78X1=640-80+1+1/78=561+1/78=561又1/78(224+1/222)×1/223=(223+1+/222)X1/223=【223+(1+1/222)】X1/223=(223+223/222)X1/223...