If a cylindrical wood with a surface area of 18.84 square decimeters and a side area of 12.56 square decimeters is sawed into 3 sections, how much square decimeters does the surface area increase?
把一个表面积是18.84平方分米，侧面积是12.56平方分米的圆柱形木料，锯成3段，表面积增加多少平方分米．
<gadget id="calculator">18.84 - 12.56</gadget>
<output>6.28</output>

<gadget id="calculator">6.28 / 2</gadget>
<output>3.14</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>