cylindrical piece of steel is 1 meter long. After being cut into two pieces, the surface area increases by 20 square decimeters. What is the original volume of the steel piece in cubic decimeters?
一条圆柱钢材，长1米，截成两段后表面积增加20平方分米，这条钢材原来的体积是多少立方分米．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 1 * 10</gadget>
<output>100</output>

<result>100</result>