A 3-meter-long square steel, when it is cut into two sections, the surface area increases by 80dm**3, what is the original volume of the square steel?
一根3米长的方钢，把它横截成2段时，表面积增加80dm**3，原来方钢的体积是多少．
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<gadget id="calculator">40 * 3 * 10</gadget>
<output>1_200</output>

<result>1_200</result>