Calculation: (1/1)+(1/2)+(2/2)+(1/2)+(1/3)+(2/3)+(3/3)+(2/3)+ (1/3)+…+(1/1999)+(2/1999)+…+(1998/1999)+(1999/1999)+(1998/1999)+…+(2/1999)+(1 /1999).
计算：(1/1)+(1/2)+(2/2)+(1/2)+(1/3)+(2/3)+(3/3)+(2/3)+(1/3)+…+(1/1999)+(2/1999)+…+(1998/1999)+(1999/1999)+(1998/1999)+…+(2/1999)+(1/1999)．
<gadget id="calculator">1 + 1_999</gadget>
<output>2_000</output>

<gadget id="calculator">1_999 - 1</gadget>
<output>1_998</output>

<gadget id="calculator">1_998 / 1</gadget>
<output>1_998</output>

<gadget id="calculator">1_998 + 1</gadget>
<output>1_999</output>

<gadget id="calculator">1_999 / 2</gadget>
<output>1_999/2 = around 999.5</output>

<gadget id="calculator">2_000 * (1_999/2)</gadget>
<output>1_999_000</output>

<result>1_999_000</result>