(1/20)+(1/30)+(1/42)+...+(1/132).
(1/20)+(1/30)+(1/42)+…+(1/132)．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/4) - (1/12)</gadget>
<output>1/6 = around 0.166667</output>

<result>1/6 = around 0.166667</result>