|1/2|-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|.|1/2012-1/2011|
问题描述：
|1/2|-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|.|1/2012-1/2011|
理由
答
|1/2-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|.|1/2012-1/2011|
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……+1/2011-1/2012
=1-1/2012
=2011/2012理由！！！|1/2-1|=1-1/2|1/3-1/2|=1/2-1/3|1/4-1/3|=1/3-1/4|1/5-1/4|=1/4-1/5……………………....|1/2012-1/2011|=1/2011-1/2012怎样并同类项？中间相互抵消，只剩下两头的1-1/2012=2011/2012