How long did it take to sleep from 9:00 pm to 7:00 am the next day?
从晚上9时睡觉到第二天早上7时共多少时．
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

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

<result>10</result>