There were 987 passengers on a train, 453 got off at the first stop, and 690 boarded. How many passengers are on the train at this time?
一列火车上原有乘客987人，到第一站时下车453人，上车690人，这时火车上有多少乘客？
<gadget id="calculator">987 - 453</gadget>
<output>534</output>

<gadget id="calculator">534 + 690</gadget>
<output>1_224</output>

<result>1_224</result>