In the math class, only Wang Ming distributes homework books, and it takes 12 minutes to distribute them. Only Li Hong distributes them, and it takes 6 minutes to distribute them. If two people distribute together, how many minutes can it be finished?
数学课上分发作业本，只让王铭分发，需要12分钟发完，只让李红分发，需要6分钟发完．如果两人一起分发，几分钟可以发完？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

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

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

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

<result>4</result>