Xiaoqiang went to bed at 9:00 every night and got up at 7:00 the next morning. How many hours did he sleep in total?
小强每天晚上9时睡觉，第2天早上7时起床，他一共睡了几个小时？
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<result>10</result>