There were 986 passengers on the train from Beijing to Shanghai, 639 people got off at Jinan Station, and 587 people got on the train. Did the number of passengers on the train increase or decrease? How many passengers are on the train at this time?
从北京开往上海的火车上有乘客986人，到济南站下车639人，上车587人，这时火车上的乘客是增加了还是减少了？这时火车上有乘客多少人？
<gadget id="calculator">986 - 639</gadget>
<output>347</output>

<gadget id="calculator">347 + 587</gadget>
<output>934</output>

<result>934</result>