Scientific research shows that it is most reasonable for children over the age of 8 to arrange a day's activities and sleep time at a ratio of 5:3. Do you know how many hours a child over the age of 8 should sleep a day?
科学研究表明，8岁以上的儿童按5：3安排一天的活动与睡眠的时间是最合理的，你知道8岁以上的儿童一天应睡几个小时吗？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">24 * (3/8)</gadget>
<output>9</output>

<result>9</result>