A rectangular iron plate with a length of 40 centimeters and a width of 30 centimeters, cut off its four corners into a square with a side length of 4 centimeters, and then weld it into a box without a cover. What is its volume in liters?
一块长40厘米、宽30厘米的长方形铁板，把它的四个角分别切掉边长为4厘米的正方形，然后焊接成一个无盖的盒子．它的容积是多少升？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">40 - 8</gadget>
<output>32</output>

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

<gadget id="calculator">4 / 1_000</gadget>
<output>1/250 = around 0.004</output>

<gadget id="calculator">32 * 22 * (1/250)</gadget>
<output>352/125 = around 2.816</output>

<result>352/125 = around 2.816</result>