Plant trees on both sides of a 40-meter road. There are 22 trees planted from the beginning to the end. It is known that the distance between two adjacent trees is equal. What is the distance between two adjacent trees.
在一条40米的大路两侧栽树，从起点到终点一共栽了22棵，已知相邻两棵树之间的距离都相等．相邻两棵树之间的距离是多少．
<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<gadget id="calculator">11 - 1</gadget>
<output>10</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<result>4</result>