The train travels x (km) per hour, the speed of the plane is 5.4 times that of the train, how many kilometers does the plane travel more than the train per hour.
火车每小时行x(km)，飞机的速度是火车的5.4倍，飞机每小时比火车多行多少km．
<gadget id="calculator">5.4 - 1</gadget>
<output>4.4</output>

<result>4.4</result>