A bridge is 2,000 meters long. When a train passes the bridge, it travels 250 meters per minute. It takes 10 minutes for the train to leave the bridge. How long is the train body?
一座大桥全长2000米，一列火车通过大桥时每分钟行驶250米，从火车头开始上桥到车尾离开桥共需10分钟，这列火车车身有多长？
<gadget id="calculator">10 * 250</gadget>
<output>2_500</output>

<gadget id="calculator">2_500 - 2_000</gadget>
<output>500</output>

<result>500</result>