(1-(1/2)*(1/2))*(1-(1/3)*(1/3))*(1-(1/4)*(1/4))*...* (1-(1/2005)*(1/2005))=how much.
(1-(1/2)*(1/2))*(1-(1/3)*(1/3))*(1-(1/4)*(1/4))*…*(1-(1/2005)*(1/2005))=多少．
<gadget id="calculator">1_003 / 2_005</gadget>
<output>1_003/2_005 = around 0.500249</output>

<result>1_003/2_005 = around 0.500249</result>