A train is 508 meters long, which is 4 meters longer than the sum of the lengths of 42 buses. How many meters is a bus?
一列火车长508米，比42辆公共汽车的长度总和还长4米，一辆公共汽车长多少米？
<gadget id="calculator">508 - 4</gadget>
<output>504</output>

<gadget id="calculator">504 / 42</gadget>
<output>12</output>

<result>12</result>