Xiao Ming and his father take the train to Beijing to play. Each train ticket is 108 yuan. Xiao Ming and his father take the train back and forth. How much does it cost?
小明和爸爸乘火车到北京去玩，每张火车票108元，小明和爸爸来回都坐火车，一共需要多少钱？
<gadget id="calculator">108 * 2 * 2</gadget>
<output>432</output>

<result>432</result>