Calculation: ((1-(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+…+(1/49)-(1/50)) /((1/(1+51))+(1/(2+52))+(1/(3+53))+(1/(4+54))+…+(1/(24+ 74))+(1/(25+75)))).
计算：((1-(1/2)+(1/3)-(1/4)+(1/5)-(1/6)+…+(1/49)-(1/50))/((1/(1+51))+(1/(2+52))+(1/(3+53))+(1/(4+54))+…+(1/(24+74))+(1/(25+75))))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / (1/2)</gadget>
<output>2</output>

<result>2</result>