According to statistics, the number of days with moderate air quality pollution in Zhengzhou in November 2014 was 18 days, accounting for the total number of days in this month.
据统计，郑州市2014年11月份空气质量中度污染的天数为18天，占本月总天数的多少．
<gadget id="calculator">18 / 30</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>