Xiao Li went to bed at 9 o'clock in the evening and got up at 6 o'clock the next morning. How many hours did she sleep in total?
小丽晚上9时睡觉，第二天早上6时起床，她一共睡了多少小时．
<gadget id="calculator">3 + 6</gadget>
<output>9</output>

<result>9</result>