The train departs from station A at 10:00 p.m. and arrives at station B at 7:00 a.m. the next morning. How many hours did the train run in total?
火车晚上10时从甲站出发，第二天早晨7时到达乙站．这列火车一共行了多少小时．
<gadget id="calculator">12 - 10</gadget>
<output>2</output>

<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<result>9</result>