If a 4m long log is cut into three small logs, the surface area increases by 12dm**2, what is the original volume of this log in cubic decimeters?
把一根4m长圆木截成三段小圆木，表面积增加了12dm**2，这根圆木原来的体积是多少立方分米？
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

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

<gadget id="calculator">3 * 40</gadget>
<output>120</output>

<result>120</result>