朋友,你要明白因为（1/3-1/2）的结果为负数,所以|1/3-1/2|=-（1/3-1/2)=1/2-1/3,其它的一样
|1/2-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|+……+|1/2011-1/2010|+|1/2012-1/2011|
=1-1/2+1/2-1/3+1/3-1/4+……+1/2010-1/2011+1/2011-1/2012
=1-1/2012
=2011/2012