A piece of rectangular cardboard with a length of 50 cm and a width of 40 cm, cut off its four corners into a square with a side length of 10 cm, and then make a box without a lid. What is its volume in liters?
一块长50厘米、宽40厘米的长方形纸板，把它的四个角分别切掉边长为10厘米的正方形，然后做成一个无盖的盒子．它的容积是多少升？
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">50 - 20</gadget>
<output>30</output>

<gadget id="calculator">40 - 20</gadget>
<output>20</output>

<gadget id="calculator">10 / 1_000</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">30 * 20 * (1/100)</gadget>
<output>6</output>

<result>6</result>