newly built road is 200 meters long, and a tree is planted every 10 meters on both sides of the road. How many trees are to be planted at both ends?
一条新建的马路长200米，在路的两旁每隔10米栽一棵树，两端要种，共要种多少棵树．
<gadget id="calculator">200 / 10</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>