(1/3)+(1/(3*5))+(1/(5*7))+…+(1/(2013*2015)).
(1/3)+(1/(3*5))+(1/(5*7))+…+(1/(2013*2015))．
<gadget id="calculator">1 / 2_015</gadget>
<output>1/2_015 = around 0.000496</output>

<gadget id="calculator">1 - (1/2_015)</gadget>
<output>2_014/2_015 = around 0.999504</output>

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

<gadget id="calculator">(2_014/2_015) * (1/2)</gadget>
<output>1_007/2_015 = around 0.499752</output>

<result>1_007/2_015 = around 0.499752</result>