(1-(1/(2**2)))*(1-(1/(3**2)))*(1-(1/(4**2)))*...*(1- (1/(2006**2))).
(1-(1/(2**2)))*(1-(1/(3**2)))*(1-(1/(4**2)))*…*(1-(1/(2006**2)))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2_007 / 2_006</gadget>
<output>2_007/2_006 = around 1.000499</output>

<gadget id="calculator">(1/2) * (2_007/2_006)</gadget>
<output>2_007/4_012 = around 0.500249</output>

<result>2_007/4_012 = around 0.500249</result>