If two cubes with side lengths of 20 cm are put together to form a cuboid, is the surface area of the cuboid equal to the sum of the surface areas of the two cubes? How much is the difference?
将两个棱长是20厘米的正方体拼成一个长方体，长方体的表面积与两个正方体的表面积之和是否相等？相差多少？
<gadget id="calculator">20 * 20 * 2</gadget>
<output>800</output>

<result>800</result>