Calculation: (1/(2*3*1999))+(1/(3*4*1999))+(1/(4*5*1999))+(1/(5*6*1999)).
计算：(1/(2*3*1999))+(1/(3*4*1999))+(1/(4*5*1999))+(1/(5*6*1999))．
<gadget id="calculator">2 * 3 * 1_999</gadget>
<output>11_994</output>

<gadget id="calculator">1 / 11_994</gadget>
<output>1/11_994 = around 0.000083</output>

<gadget id="calculator">3 * 4 * 1_999</gadget>
<output>23_988</output>

<gadget id="calculator">1 / 23_988</gadget>
<output>1/23_988 = around 0.000042</output>

<gadget id="calculator">4 * 5 * 1_999</gadget>
<output>39_980</output>

<gadget id="calculator">1 / 39_980</gadget>
<output>1/39_980 = around 0.000025</output>

<gadget id="calculator">5 * 6 * 1_999</gadget>
<output>59_970</output>

<gadget id="calculator">1 / 59_970</gadget>
<output>1/59_970 = around 0.000017</output>

<gadget id="calculator">(1/11_994) + (1/23_988) + (1/39_980) + (1/59_970)</gadget>
<output>1/5_997 = around 0.000167</output>

<result>1/5_997 = around 0.000167</result>