In a month of May, cloudy days are less than sunny days (1/3), rainy days are less than sunny days (3/5), how many days are sunny in this month.
某五月份中，阴天比晴天少(1/3)，雨天比晴天少(3/5)，这个月多少天是晴天．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/3) + (2/5)</gadget>
<output>31/15 = around 2.066667</output>

<gadget id="calculator">31 / (31/15)</gadget>
<output>15</output>

<result>15</result>