Calculation: (1-(1/2))*(1+(1/2)*(1-(1/3))*(1+(1/3))*…*(1-(1/9 ))*(1+(1/9)).
计算：(1-(1/2))*(1+(1/2)*(1-(1/3))*(1+(1/3))*…*(1-(1/9))*(1+(1/9))．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">10 / 9</gadget>
<output>10/9 = around 1.111111</output>

<gadget id="calculator">(1/2) * (10/9)</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>