If a 4-meter-long cylinder of steel is cut transversely into 2 sections, the surface area is 20 square decimeters larger than the original, what is the volume of the original cylinder of steel in cubic decimeters?
把一根4米长的圆柱体钢材横切成2段，表面积比原来多20平方分米，原来圆柱体钢材的体积是多少立方分米．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 4 * 10</gadget>
<output>400</output>

<result>400</result>