A batch of goods can be transported by car A alone 6 times, car B alone can be transported 12 times, and how many times can the two cars be transported together.
一批货物，甲车单独运6次可运完，乙车单独运12次可运完，两车一起运，多少次可运完．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/6) + (1/12)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / (1/4)</gadget>
<output>4</output>

<result>4</result>