When a 5-meter-long square steel is cut into 5 sections, the surface area will increase by 80 square centimeters. What is the original volume of the square steel?
一根5米长的方钢，把它横截成5段时，表面积就增加80平方厘米，原来方钢的体积是多少？
<gadget id="calculator">80 / 8</gadget>
<output>10</output>

<gadget id="calculator">5 * 100</gadget>
<output>500</output>

<gadget id="calculator">10 * 500</gadget>
<output>5_000</output>

<result>5_000</result>