Calculation: (1/(1988*1989))+(1/(1989*1990))+(1/(1990*1991))+(1/(1991*1992))+(1/(1992*1993) )+(1/1993).
计算：(1/(1988*1989))+(1/(1989*1990))+(1/(1990*1991))+(1/(1991*1992))+(1/(1992*1993))+(1/1993)．
<gadget id="calculator">1_988 * 1_989</gadget>
<output>3_954_132</output>

<gadget id="calculator">1 / 3_954_132</gadget>
<output>1/3_954_132 = around 0</output>

<gadget id="calculator">1_989 * 1_990</gadget>
<output>3_958_110</output>

<gadget id="calculator">1 / 3_958_110</gadget>
<output>1/3_958_110 = around 0</output>

<gadget id="calculator">1_990 * 1_991</gadget>
<output>3_962_090</output>

<gadget id="calculator">1 / 3_962_090</gadget>
<output>1/3_962_090 = around 0</output>

<gadget id="calculator">1_991 * 1_992</gadget>
<output>3_966_072</output>

<gadget id="calculator">1 / 3_966_072</gadget>
<output>1/3_966_072 = around 0</output>

<gadget id="calculator">1_992 * 1_993</gadget>
<output>3_970_056</output>

<gadget id="calculator">1 / 3_970_056</gadget>
<output>1/3_970_056 = around 0</output>

<gadget id="calculator">1 / 1_993</gadget>
<output>1/1_993 = around 0.000502</output>

<gadget id="calculator">(1/3_954_132) + (1/3_958_110) + (1/3_962_090) + (1/3_966_072) + (1/3_970_056) + (1/1_993)</gadget>
<output>1/1_988 = around 0.000503</output>

<result>1/1_988 = around 0.000503</result>