A simple algorithm of 2 * 3 / 1 + 3 * 4 / 1 +... + 2009 * 2010 / 1

A simple algorithm of 2 * 3 / 1 + 3 * 4 / 1 +... + 2009 * 2010 / 1

1 / 2 * 3 + 1 / 3 * 4 +... + 1 / 2009 * 2010
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+.+(1/2009-1/2010)
=1/2-1/2010
=502/1005