A project can be completed by team A alone in 6 days and by team B in 12 days. How many days will it take for the two teams to work on half of the project?
一件工程，甲队单独做要6天完成，乙队单独做要12天完成．两队合作这件工程的一半需要几天？
<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 / 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">(1/2) / (1/4)</gadget>
<output>2</output>

<result>2</result>