Xiao Li and Xiao Zhang collaborated on a job, and completed all (6/7) in 6 days. It is known that Xiao Li completed it in 14 days alone, and how many days did Xiao Zhang complete it alone?
小李和小张合作一件工作，6天做完全部的(6/7)，已知小李单独做14天完成，小张单独做几天完成？
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(6/7) / 6</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 14</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">(1/7) - (1/14)</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">1 / (1/14)</gadget>
<output>14</output>

<result>14</result>