Process a batch of parts. If Master Wang works alone, it will take (1/3) hours; if Master Li works alone, it will take (1/4) hours. Now Master Wang and Master Li are processing together at the same time. How long will it take to process this batch of parts?
加工一批零件．如果王师傅单独加工要(1/3)小时；如果李师傅单独加工要(1/4)小时．现在王师傅和李师傅同时一起加工，加工完成这批零件需要多长时间？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / (1/3)</gadget>
<output>3</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<result>1/7 = around 0.142857</result>