There were originally 46 people on the bus. When it arrived at the station, 19 people got off and 12 got on. How many people are on the bus now? What is the column
公交车上原有46人，到站时有19人下车，12人上车，现在车上有多少人？列式为多少
<gadget id="calculator">46 - 19</gadget>
<output>27</output>

<gadget id="calculator">27 + 12</gadget>
<output>39</output>

<result>39</result>