Lao Li completed a task in 80 days, saving time (1/5) compared to the plan. How many days do you plan to use?
老李用80天时间完成了一项任务，比计划节省时间(1/5)．计划用多少天？
<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">80 / (4/5)</gadget>
<output>100</output>

<result>100</result>