An 8m long wire is used up (5/8), leaving ((())/(())).
一根8m长的电线，用去(5/8)，还剩下((())/(()))．
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>