A piece of rectangular cardboard with a length of 30 cm and a width of 20 cm. Remove a small square with a side length of 5 cm from each of the four corners of the cardboard and assemble it into a carton without a lid. What is the volume of the carton? ?
一块长方形纸板，长30厘米，宽20厘米，在这张纸板的四个角上分别去掉一个边长为5厘米的小正方形，然后拼成一个无盖的纸盒，这个纸盒的容积是多少？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<gadget id="calculator">20 - 10</gadget>
<output>10</output>

<gadget id="calculator">20 * 10 * 5</gadget>
<output>1_000</output>

<result>1_000</result>