(1-(1/(2**2)))(1-(1/(3**2)))(1-(1/(4**2)))…(1-(1/( 2004**2))).
(1-(1/(2**2)))(1-(1/(3**2)))(1-(1/(4**2)))…(1-(1/(2004**2)))．
<gadget id="calculator">2_004 ** 2</gadget>
<output>4_016_016</output>

<gadget id="calculator">1 / 4_016_016</gadget>
<output>1/4_016_016 = around 0</output>

<gadget id="calculator">1 - (1/4_016_016)</gadget>
<output>4_016_015/4_016_016 = around 1</output>

<gadget id="calculator">(4_016_015/4_016_016) / 2</gadget>
<output>4_016_015/8_032_032 = around 0.5</output>

<gadget id="calculator">2_005 / 2_004</gadget>
<output>2_005/2_004 = around 1.000499</output>

<gadget id="calculator">(4_016_015/8_032_032) * (2_005/2_004)</gadget>
<output>8_052_110_075/16_096_192_128 = around 0.500249</output>

<result>8_052_110_075/16_096_192_128 = around 0.500249</result>