If A#B=((BA)/(A*B)), then 1#2-2#3-3#4-…-2002#2003-2003#2004=how much.
如果A#B=((B-A)/(A*B))，那么1#2-2#3-3#4-…-2002#2003-2003#2004=多少．
<gadget id="calculator">1 / 2_004</gadget>
<output>1/2_004 = around 0.000499</output>

<result>1/2_004 = around 0.000499</result>