Students plant trees on both sides of a road (both ends must be planted), the distance between every two trees is 6 meters, and a total of 180 trees are planted. How long is this road in meters?
同学们在一条公路的两边栽树(两端都要栽)，每两棵树中间的距离是6米，共栽了180棵树，这条公路长多少米？
<gadget id="calculator">180 / 2</gadget>
<output>90</output>

<gadget id="calculator">90 - 1</gadget>
<output>89</output>

<gadget id="calculator">89 * 6</gadget>
<output>534</output>

<result>534</result>