wooden box with a lid is 20 cm long, 15 cm wide, and 12 cm high. A layer of paint is applied to its shell. How many square centimeters is the area to be painted?
一只有盖的木盒，长20厘米，宽15厘米，高12厘米，在它的外壳涂上一层油漆，要涂的面积是多少平方厘米？
<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">15 * 12</gadget>
<output>180</output>

<gadget id="calculator">300 + 240 + 180</gadget>
<output>720</output>

<gadget id="calculator">720 * 2</gadget>
<output>1_440</output>

<result>1_440</result>