A bus from Qucheng to Sanhui got off 12 people on the way, and 19 people got on the bus. When it arrived at the station, there were 34 people on board. How many people were on board the bus when it left the station?
一辆从渠城开往三汇的大客车在途中下车12人，上车19人，到站时车上共坐有34．这辆大客车出站时车上共坐有多少人？
<gadget id="calculator">34 - 9</gadget>
<output>25</output>

<gadget id="calculator">25 + 12</gadget>
<output>37</output>

<result>37</result>