A tunnel is 3506 meters long. A train travels 35 meters per second through this tunnel. It takes 127 seconds from the time the locomotive enters the tunnel to when the train leaves the tunnel. How long is the train body?
一条隧道长3506米，一列火车通过这条隧道每秒行35米，从火车头进入隧道到火车尾离开隧道共需127秒．这列火车车身长多少米？
<gadget id="calculator">35 * 127</gadget>
<output>4_445</output>

<gadget id="calculator">4_445 - 3_506</gadget>
<output>939</output>

<result>939</result>