|1/2-1|+|1/3-1/2|+|1/4-1/3|+.......+|1/2010-1/2009|=(1-1/2)+(1/2-1/3)+(1/3-1/4)+.....+(1/2008-1/2009)+(1/2009-1/2010)=1+(-1/2+1/2)+(-1/3+1/3)+(-1/4+1/4)+.....+(-1/2009+1/2009)+1/2010=1+0+0+0+....+0+1/2010=2011/2010