A piece of cylindrical wood with a length of 4 meters, if it is sawn into 3 pieces, the surface area increases by 20 square centimeters, what is the original volume of the wood in cubic centimeters?
一段长4米的圆柱形木头，如果把它锯成3段，表面积增加20平方厘米，原来木头的体积是多少立方厘米？
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">4 * 100</gadget>
<output>400</output>

<gadget id="calculator">5 * 400</gadget>
<output>2_000</output>

<result>2_000</result>