(1/(2000*2001))+(1/(2001*2002))+(1/(2002*2003))+…+(1/(2007*2008))+(1/(2008*2009) )+(1/(2009*2010)).
(1/(2000*2001))+(1/(2001*2002))+(1/(2002*2003))+…+(1/(2007*2008))+(1/(2008*2009))+(1/(2009*2010))．
<gadget id="calculator">1 / 2_009</gadget>
<output>1/2_009 = around 0.000498</output>

<gadget id="calculator">1 / 2_010</gadget>
<output>1/2_010 = around 0.000498</output>

<gadget id="calculator">(1/2_009) - (1/2_010)</gadget>
<output>1/4_038_090 = around 0</output>

<result>1/4_038_090 = around 0</result>