On a summer day, the time ratio of day to night is 7:5. How many hours is the night.
夏季的一天，白天使夜间的时间比7：5．这天夜间是多少小时．
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">24 * (5/12)</gadget>
<output>10</output>

<result>10</result>