If a willow tree is planted every 5 meters on both sides of a 150-meter-long road, how many willows should be planted in total?
在一条长150米的公路两旁每隔5米栽一棵柳树，一共要栽多少棵？
<gadget id="calculator">150 / 5</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>