The city garden plan is to plant trees on both sides of a newly built Yingbin Avenue with a total length of 100 meters, and plant one tree every 5 meters (planting at both ends), how many saplings are needed in total.
城市园林规划在新修的一条全长100米的迎宾大道两边植树，每隔5米栽一棵(两端要栽)，一共需要树苗多少棵．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

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

<gadget id="calculator">21 * 2</gadget>
<output>42</output>

<result>42</result>