If a 4-meter-long cylindrical stick is sawn into three pieces, the surface area increases by 12 square decimeters. What is the original volume of the cylindrical wooden stick?
把一根4米长的圆柱形木条锯成三段，表面积增加了12平方分米，这根圆柱形木条原来的体积是多少立方分米．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 4 * 10</gadget>
<output>120</output>

<result>120</result>