When a train arrives at station A, 43 people get off and 104 get on, and there are still 584 people on board. How many people were there on the train? (Solving problems with equations)
一列火车到A站时，有43人下车，104人上车，这时车上还有584人．列车上原有多少人？(用方程解决问题)
<gadget id="calculator">584 - 104</gadget>
<output>480</output>

<gadget id="calculator">43 + 480</gadget>
<output>523</output>

<result>523</result>