To dig a 1,000-meter-long channel, 1/5 of the total length was dug in the first 5 days. How many days will it take to finish digging according to this progress?
挖一条长1000米渠道，前5天挖了总长的(1/5)，按这样的进度还需要几天挖完？
<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">(4/5) / (1/25)</gadget>
<output>20</output>

<result>20</result>