(1/(1*2))+(1/(2*3))+(1/(3*4))+...+(1/(7*8))=how much.
(1/(1*2))+(1/(2*3))+(1/(3*4))+…+(1/(7*8))=多少．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<result>7/8 = around 0.875</result>