A cuboid ventilation pipe is 18 meters long, 9 meters wide, and 4 meters high. What is its surface area in square meters?
一个长方体的通风管，长18米，宽9米，高4米，求它的表面积是多少平方米？
<gadget id="calculator">18 * 9 * 2</gadget>
<output>324</output>

<gadget id="calculator">18 * 4 * 2</gadget>
<output>144</output>

<gadget id="calculator">324 + 144</gadget>
<output>468</output>

<result>468</result>