Process a batch of parts, master Huang (1/5) days to complete, Hong master (1/7) days to complete. The processing task can be completed within a few days of cooperation between the two.
加工一批零件，黄师傅(1/5)天完成，洪师傅(1/7)天完成．两人合作多少天就可以完成加工任务．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / (1/5)</gadget>
<output>5</output>

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

<gadget id="calculator">1 / (1/7)</gadget>
<output>7</output>

<gadget id="calculator">5 + 7</gadget>
<output>12</output>

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

<result>1/12 = around 0.083333</result>