A rectangular flower bed is 8 meters long and 4 meters wide. Uncle Wang is going to install guardrails around the flower bed. If the guardrails cost 8 yuan per meter, how much will it cost to install the guardrails?
一个长方形花坛的长是8米，宽是4米．王叔叔准备给这个花坛的四周安上护栏，如果护栏每米8元钱，安装护栏需要多少钱？
<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 2 * 8</gadget>
<output>192</output>

<result>192</result>