The students planted trees on one side of the path with a total length of 120 meters, and planted one tree every 4 meters (both ends must be planted). How many trees are needed in total?
同学们在全长120米的小路一边植树，每隔4米栽一棵(两端都要栽)．一共要多少棵树？
<gadget id="calculator">120 / 4</gadget>
<output>30</output>

<gadget id="calculator">30 + 1</gadget>
<output>31</output>

<result>31</result>