The length of a cuboid is 5dm, the width is 4dm, and the height is 2.5dm, what is its surface area dm**2.
一个长方体的长是5dm，宽是4dm，高是2.5dm，它的表面积是多少dm**2．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">5 * 2.5</gadget>
<output>12.5</output>

<gadget id="calculator">4 * 2.5</gadget>
<output>10</output>

<gadget id="calculator">20 + 12.5 + 10</gadget>
<output>42.5</output>

<gadget id="calculator">42.5 * 2</gadget>
<output>85</output>

<result>85</result>