Xiao Ming measures the volume of an irregular stone. From the inside, the length of the cuboid container is 20cm, the width is 15cm, and the height of the water surface is 8cm. After immersing the stone in the container, the height of the water surface is 12cm. Please calculate this stone block volume.
小明测量一块不规则石块的体积，从里面量得长方体容器的长是20cm，宽是15cm，水面高8cm，将石块浸没在容器后，量得水面的高12cm，请你算出这块石块的体积．
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">20 * 15 * 4</gadget>
<output>1_200</output>

<result>1_200</result>