Studies have shown that working in front of a computer for a long time is prone to dry eye syndrome. According to a survey by a medical institution, 80 people had dry eye syndrome, accounting for about 4/25 of the number of people surveyed. So how many people are there who do not have dry eye syndrome?
研究表明：长期在电脑前工作，容易出现干眼症．一家医学机构调查显示，有80人出现干眼症，约占调查人数的(4/25)．那么没有出现干眼症的被调查者有多少人？
<gadget id="calculator">4 / 25</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">80 / (4/25)</gadget>
<output>500</output>

<gadget id="calculator">500 - 80</gadget>
<output>420</output>

<result>420</result>