The area of a rectangular vegetable field is 2000 square meters, its length is 50 meters, and there is a fence around it, what is the total length of the fence in meters?
一块长方形的菜地的面积是2000平方米，它的长50米，在它的四周围上一圈篱笆，篱笆的总长是多少米？
<gadget id="calculator">2_000 / 50</gadget>
<output>40</output>

<gadget id="calculator">50 + 40</gadget>
<output>90</output>

<gadget id="calculator">90 * 2</gadget>
<output>180</output>

<result>180</result>