To transport a pile of coal, how many hours will it take to transport this pile of coal (1/18) per hour on average.
运一堆煤，平均每小时运这堆煤的(1/18)，运完这堆煤要多少小时．
<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">1 / (1/18)</gadget>
<output>18</output>

<result>18</result>