A train leaves at 10 o'clock in the evening and arrives at the station at 6 o'clock the next day. How many hours has the train been running?
一列火车晚上10时开车，第二天6时到站，火车一共开了多少小时．
<gadget id="calculator">12 - 10</gadget>
<output>2</output>

<gadget id="calculator">2 + 6</gadget>
<output>8</output>

<result>8</result>