A cuboid plank is 3.5 meters long, 8 decimeters wide, and 10 centimeters thick. What is the surface area of this plank?
一块长方体木板长3.5米，宽8分米，厚10厘米，这块木板的表面积是多少平方分米？
<gadget id="calculator">3.5 * 10 * 8</gadget>
<output>280</output>

<gadget id="calculator">10 / 10</gadget>
<output>1</output>

<gadget id="calculator">3.5 * 10 * 1</gadget>
<output>35</output>

<gadget id="calculator">8 * 1</gadget>
<output>8</output>

<gadget id="calculator">280 + 35 + 8</gadget>
<output>323</output>

<gadget id="calculator">323 * 2</gadget>
<output>646</output>

<result>646</result>