The students planted trees on one side of the path with a total length of 100 meters, and planted one tree every 5 meters (planted at both ends). How many saplings are needed in total.
同学们在全长100米的小路一边植树，每隔5米栽一棵(两端都栽)．一共需要多少棵树苗．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">20 + 1</gadget>
<output>21</output>

<result>21</result>