The rectangular vegetable field is 120 meters long and 36 meters wide. There is a fence around the vegetable field. What is the approximate length of the fence?
长方形菜地长120米，宽36米，沿菜地四周围有一圈篱笆，篱笆大约长多少米
<gadget id="calculator">120 + 36</gadget>
<output>156</output>

<gadget id="calculator">156 * 2</gadget>
<output>312</output>

<result>312</result>