|1-1/2|+|1/3-1/2|+…+|1/1999-1/1998|=?
问题描述:
|1-1/2|+|1/3-1/2|+…+|1/1999-1/1998|=?
答
原式=1-1/2+1/2-1/3+1/3-1/4+……+1/1997-1/1998+1/1998-1/1999
=1-1/1999
=1998/1999