Willows and crabapple trees are planted around the circular pond in the park. There are 2 crabapple trees between every two willow trees. There are 240 crabapple trees in total. How many willow trees are there?
环绕着公园的圆形池塘边栽着柳树和海棠树，每相邻2棵柳树之间有2棵海棠树，一共有240棵海棠树．柳树有多少棵？
<gadget id="calculator">240 / 2</gadget>
<output>120</output>

<result>120</result>