(1/(1+2))+(1/(1+2+3))+(1/(1+2+3+4))+…(1/(1+2+3+4+… +200)).
(1/(1+2))+(1/(1+2+3))+(1/(1+2+3+4))+…(1/(1+2+3+4+…+200))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 201</gadget>
<output>1/201 = around 0.004975</output>

<gadget id="calculator">(1/2) - (1/201)</gadget>
<output>199/402 = around 0.495025</output>

<gadget id="calculator">(199/402) * 2</gadget>
<output>199/201 = around 0.99005</output>

<result>199/201 = around 0.99005</result>