The price of a toy car is 108 yuan, and the price of a toy train is twice that of a car. How much does it cost to buy two toy trains?
一辆玩具小汽车的售价是108元，玩具火车的价格是小汽车的2倍．买两个玩具火车要付多少元？
<gadget id="calculator">108 * 2</gadget>
<output>216</output>

<gadget id="calculator">216 * 2</gadget>
<output>432</output>

<result>432</result>