If a cuboid wood has a cross-sectional area of 9cm**2, if it is cut into two sections, how much will the surface area increase by cm**2?
一根长方体木料，它的横截面积是9cm**2，把它截成2段，表面积增加多少cm**2．
<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>