(1/(2*5))+(1/(5*8))+(1/(8*11))+…+(1/(2006*2009))+(1/(2009*2012) ).
(1/(2*5))+(1/(5*8))+(1/(8*11))+…+(1/(2006*2009))+(1/(2009*2012))．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 2_012</gadget>
<output>1/2_012 = around 0.000497</output>

<gadget id="calculator">(1/2) - (1/2_012)</gadget>
<output>1_005/2_012 = around 0.499503</output>

<gadget id="calculator">(1/3) * (1_005/2_012)</gadget>
<output>335/2_012 = around 0.166501</output>

<result>335/2_012 = around 0.166501</result>