Calculation: ((1/2)-1)*((1/3)-1)*((1/4)-1)*…*((1/2013)-1)=how much.
计算：((1/2)-1)*((1/3)-1)*((1/4)-1)*…*((1/2013)-1)=多少．
<gadget id="calculator">1 / 2_013</gadget>
<output>1/2_013 = around 0.000497</output>

<result>1/2_013 = around 0.000497</result>