(1+(1/2002)+(1/2004)+(1/2006))*((1/2002)+(1/2004)+(1/2006)+(1/2008))-(1 +(1/2002)+(1/2004)+(1/2006)+(1/2008))*((1/2002)+(1/2004)+(1/2006))=how much.
(1+(1/2002)+(1/2004)+(1/2006))*((1/2002)+(1/2004)+(1/2006)+(1/2008))-(1+(1/2002)+(1/2004)+(1/2006)+(1/2008))*((1/2002)+(1/2004)+(1/2006))=多少．
<gadget id="calculator">1 / 2_002</gadget>
<output>1/2_002 = around 0.0005</output>

<gadget id="calculator">1 / 2_004</gadget>
<output>1/2_004 = around 0.000499</output>

<gadget id="calculator">1 / 2_006</gadget>
<output>1/2_006 = around 0.000499</output>

<gadget id="calculator">1 + (1/2_002) + (1/2_004) + (1/2_006)</gadget>
<output>2_015_034_023/2_012_022_012 = around 1.001497</output>

<gadget id="calculator">1 / 2_008</gadget>
<output>1/2_008 = around 0.000498</output>

<gadget id="calculator">(1/2_002) + (1/2_004) + (1/2_006) + (1/2_008)</gadget>
<output>2_015_035_025/1_010_035_050_024 = around 0.001995</output>

<gadget id="calculator">(2_015_034_023/2_012_022_012) * (2_015_035_025/1_010_035_050_024)</gadget>
<output>4_060_364_132_911_655_575/2_032_212_753_539_809_128_288 = around 0.001998</output>

<gadget id="calculator">1 + (1/2_002) + (1/2_004) + (1/2_006) + (1/2_008)</gadget>
<output>1_012_050_085_049/1_010_035_050_024 = around 1.001995</output>

<gadget id="calculator">(1/2_002) + (1/2_004) + (1/2_006)</gadget>
<output>3_012_011/2_012_022_012 = around 0.001497</output>

<gadget id="calculator">(1_012_050_085_049/1_010_035_050_024) * (3_012_011/2_012_022_012)</gadget>
<output>3_048_305_988_718_523_539/2_032_212_753_539_809_128_288 = around 0.0015</output>

<gadget id="calculator">(4_060_364_132_911_655_575/2_032_212_753_539_809_128_288) - (3_048_305_988_718_523_539/2_032_212_753_539_809_128_288)</gadget>
<output>1/2_008 = around 0.000498</output>

<result>1/2_008 = around 0.000498</result>