(1/(3*4))+(1/(4*5))+(1/(5*6))+...+(1/(74*75)).
(1/(3*4))+(1/(4*5))+(1/(5*6))+…+(1/(74*75))．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 75</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">(1/3) - (1/75)</gadget>
<output>8/25 = around 0.32</output>

<result>8/25 = around 0.32</result>