Divide a cube with an edge length of 20 decimeters into two identical cuboids, how much dm**2 is the surface area increased?
把一个棱长为20分米的正方体分成两个相同的长方体，表面积增加了多少dm**2．
<gadget id="calculator">20 * 20 * 2</gadget>
<output>800</output>

<result>800</result>