The school playground is 20 meters long, and the width is 4 meters shorter than the length. Xiao Ming ran 3 laps around the playground. How many meters did he run in total?
学校操场长是20米，宽比长短4米，小明围绕操场跑了3圈，一共跑了多少米？
<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">20 + 16</gadget>
<output>36</output>

<gadget id="calculator">36 * 2 * 3</gadget>
<output>216</output>

<result>216</result>