There is a cuboid glass container with a length of 20 cm and a width of 10 cm. If a stone is put in, the height of the water surface is 6 cm. After removing the stone, the height of the water surface is 4 cm. What is the volume of the stone in cubic centimeters?
有一个长方体玻璃容器，长20厘米，宽10厘米，如果放入一个石块，水面的高度是6厘米，拿掉石块以后，水面高度是4厘米，求石块的体积是多少立方厘米？
<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">20 * 10 * 2</gadget>
<output>400</output>

<result>400</result>