job can be done in (1/6) days alone, and B can be done in (1/5) days alone. How many days can A and B cooperate to complete?
一项工作甲单独做(1/6)天完成，乙单独做(1/5)天可完成．甲、乙合作多少天可以完成．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<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">6 + 5</gadget>
<output>11</output>

<gadget id="calculator">1 / 11</gadget>
<output>1/11 = around 0.090909</output>

<result>1/11 = around 0.090909</result>