Group split item: Simplify (1/(3*1))+(1/(4*2))+(1/(5*3))+(1/(6*4))+…+(1 /(1999*1997))+(1/(2000*1998))=how much.
分组裂项：化简(1/(3*1))+(1/(4*2))+(1/(5*3))+(1/(6*4))+…+(1/(1999*1997))+(1/(2000*1998))=多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 1_999</gadget>
<output>1/1_999 = around 0.0005</output>

<gadget id="calculator">1 / 2_000</gadget>
<output>1/2_000 = around 0.0005</output>

<gadget id="calculator">(1/2) - (1/1_999) - (1/2_000)</gadget>
<output>1_995_001/3_998_000 = around 0.499</output>

<gadget id="calculator">1 + (1_995_001/3_998_000)</gadget>
<output>5_993_001/3_998_000 = around 1.499</output>

<gadget id="calculator">(1/2) * (5_993_001/3_998_000)</gadget>
<output>5_993_001/7_996_000 = around 0.7495</output>

<result>5_993_001/7_996_000 = around 0.7495</result>