(5/(2*7))+(5/(7*12))+(5/(12*17))+...+(5/(97*102)).
(5/(2*7))+(5/(7*12))+(5/(12*17))+…+(5/(97*102))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 102</gadget>
<output>1/102 = around 0.009804</output>

<gadget id="calculator">(1/2) - (1/102)</gadget>
<output>25/51 = around 0.490196</output>

<result>25/51 = around 0.490196</result>