Xiao Xing went to bed at 8 o'clock in the evening and got up at 5 o'clock the next day. How many hours did she sleep?
小星晚上8时睡觉，第二天5时起床，她睡了多少小时．
<gadget id="calculator">24 - 20</gadget>
<output>4</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<result>9</result>