1/1*2+1/2*3+1/3*4.+1/2003*2004

问题描述:

1/1*2+1/2*3+1/3*4.+1/2003*2004

=1-1/2+1/2-1/3+1/3-1/4.+1/2003-1/2004
=1-1/2004
=2003/2004