A section of road was repaired (1/2) on the first day and (1/6) on the second day, how much is the remaining length
一段路，第一天修了(1/2)，第二天修了(1/6)，还剩全长的多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/2) - (1/6)</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>