After sawing a 4-meter-long cuboid block into three pieces, the surface area increases by 8 square decimeters compared to the original one. What is the original volume of the cuboid block?
把一根长4米的长方体木块锯成三段后，表面积比原来增加了8平方分米，这块长方体木块原来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">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">2 * 40</gadget>
<output>80</output>

<result>80</result>