It takes 6 days for wild ducks to fly from Beijing to the South China Sea, and 12 days for wild geese to fly from the South China Sea to Beijing. Now that they take off from Beijing and the South China Sea at the same time, how many days can they meet?
野鸭从北京飞往南海需要6天，大雁从南海飞往北京需要12天，现在它们分别从北京、南海同时相对起飞，多少天能够相遇？
<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>