Take a rectangular iron sheet with a length of 30cm and a width of 20cm, and cut a square with a side length of 4cm from each of the four corners to make an iron box without a lid. What is the volume of this iron box?
把一张长30cm，宽20cm的长方形铁皮，从四角各剪去一个边长为4cm的正方形，做成一个无盖铁盒，这个铁盒的容积是多少？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">30 - 8</gadget>
<output>22</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<gadget id="calculator">22 * 12 * 4</gadget>
<output>1_056</output>

<result>1_056</result>