(1/13)+(1/26)+(1/52)+(1/104)+(1/208)=how much.
(1/13)+(1/26)+(1/52)+(1/104)+(1/208)=多少．
<gadget id="calculator">1 / 13</gadget>
<output>1/13 = around 0.076923</output>

<gadget id="calculator">1 / 26</gadget>
<output>1/26 = around 0.038462</output>

<gadget id="calculator">1 / 52</gadget>
<output>1/52 = around 0.019231</output>

<gadget id="calculator">1 / 104</gadget>
<output>1/104 = around 0.009615</output>

<gadget id="calculator">1 / 208</gadget>
<output>1/208 = around 0.004808</output>

<gadget id="calculator">(1/13) + (1/26) + (1/52) + (1/104) + (1/208)</gadget>
<output>31/208 = around 0.149038</output>

<result>31/208 = around 0.149038</result>