A small stone is submerged in a cuboid glass tank, the water surface is 6 cm high before immersion, and the water surface is 10 cm high after immersion (the water does not overflow). Measure the length of the glass cylinder 30 cm and the width of 20 cm from the inside, find the volume of the small stone.
在一个长方体玻璃缸中浸没一块小石头，浸没前水面高6厘米，浸没后水面高10厘米(水没有溢出)．从里面测量玻璃缸长30厘米，宽20厘米，求小石头的体积．
<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<gadget id="calculator">30 * 20 * 4</gadget>
<output>2_400</output>

<result>2_400</result>