A bridge is 2,400 meters long. A train travels 900 meters per minute when passing the bridge. It takes 3 minutes for the train to cross the bridge. How many meters is the train?
一座桥长2400米，一列火车通过大桥时每分钟行900米，从火车上桥到完全通过共用3分钟，这列火车有多少米？
<gadget id="calculator">900 * 3</gadget>
<output>2_700</output>

<gadget id="calculator">2_700 - 2_400</gadget>
<output>300</output>

<result>300</result>