A square field has 10 trees on each side, and the distance between every two adjacent trees is 5 meters. What is the perimeter of the square field in meters?
一块正方形的地，每边有10棵树，每相邻两棵树之间的距离是5米，这块正方形地的周长是多少米？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">5 * 9</gadget>
<output>45</output>

<gadget id="calculator">45 * 4</gadget>
<output>180</output>

<result>180</result>