If a cross-section is a cuboid with a side length of 1dm and sawn into three pieces, how much does the surface area increase by dm**2.
一个横截面是边长1dm的长方体木料锯成三段，表面积增加多少dm**2．
<gadget id="calculator">1 * 1 * 4</gadget>
<output>4</output>

<result>4</result>