A total of 39 trees were planted between two buildings 400 meters apart, and a tree was planted every few meters?
在两栋相距400米的楼房之间共栽树39棵，每隔几米栽一棵树？
<gadget id="calculator">39 + 1</gadget>
<output>40</output>

<gadget id="calculator">400 / 40</gadget>
<output>10</output>

<result>10</result>