If a 2-meter-long cylindrical stick is sawn into three pieces, the surface area increases by 4 square decimeters. What is the original volume of the stick?
把2米长的圆柱形木棒锯成三段，表面积增加了4平方分米，原来木棒的体积是多少立方分米．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">1 * 2 * 10</gadget>
<output>20</output>

<result>20</result>