解:∵1/1×2=1-1/2
1/2×3=½-1/3
。。。
1/2012×2013=1/2012-1/2013
∴1/1*2+1/2*3+1/3*4+...+1/2011*2012+1/2012*2013
=1-1/2+1/2-1/3+1/3-1/4+...+1/2011-1/2012+1/2012-1/2013
=1-1/2013
=2012/2013
1/1*2+1/2*3+1/3*4+...+1/2011*2012+1/2012*2013
=1-1/2+1/2-1/3+1/3-1/4+...+1/2011-1/2012+1/2012-1/2013
=1-1/2013
=2012/2013
2012