Uncle Zhang walked 3 times along the edge of a rectangular open space with a length of 120 meters and a width of 30 meters. How many meters did Uncle Zhang walk in total?
张大爷沿着一个长120米，宽30米的长方形空地的边缘走了3圈，张大爷一共走了多少米？
<gadget id="calculator">120 + 30</gadget>
<output>150</output>

<gadget id="calculator">150 * 2 * 3</gadget>
<output>900</output>

<result>900</result>