A road is 1800 meters long. Now a tree must be planted on both sides of the road every 6 meters. How many trees should be planted in total?
一条公路长1800米，现在必须在路的两旁每隔6米栽一棵树，一共要栽多少棵树？
<gadget id="calculator">1_800 / 6</gadget>
<output>300</output>

<gadget id="calculator">300 + 1</gadget>
<output>301</output>

<gadget id="calculator">301 * 2</gadget>
<output>602</output>

<result>602</result>