A small road is 90 meters long, and trees should be planted on both sides of the road, one tree every 3 meters (both ends should be planted). How many trees will be planted in total?
一段小路长90米，要在路的两旁植树，每隔3米植一棵(两端要栽)．一共要栽多少棵？
<gadget id="calculator">90 / 3</gadget>
<output>30</output>

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

<gadget id="calculator">31 * 2</gadget>
<output>62</output>

<result>62</result>