project A and B work together to complete in 5 days. Now A works for 5 days and completes (1/5) of the whole process. The rest is done by B alone. How many days will it take?
一项工程甲、乙两人合做5天完成，现在先由甲工作了5天，完成了全程的(1/5)，余下的由乙一人去做，要多少天．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/5) / 5</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(1/5) - (1/25)</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">(4/5) / (4/25)</gadget>
<output>5</output>

<result>5</result>