Calculation: (2009/(2*4))+(2009/(4*6))+(2009/(6*8))+...+(2009/(4016*4018)).
计算：(2009/(2*4))+(2009/(4*6))+(2009/(6*8))+…+(2009/(4016*4018))．
<gadget id="calculator">2_009 / 2</gadget>
<output>2_009/2 = around 1_004.5</output>

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

<gadget id="calculator">1 / 4_018</gadget>
<output>1/4_018 = around 0.000249</output>

<gadget id="calculator">(1/2) - (1/4_018)</gadget>
<output>1_004/2_009 = around 0.499751</output>

<gadget id="calculator">(2_009/2) * (1_004/2_009)</gadget>
<output>502</output>

<result>502</result>