A cuboid container is 12 centimeters high, its bottom is a square, and its sides are also exactly a square. Now there is 6 cm of water in the container. When a stone is submerged in the water, the water depth becomes 6.5 cm. What is the volume of the stone?
一个长方体容器高12厘米，底面是一个正方形，它的侧面展开恰好也是一个正方形．现在容器中装有6厘米深的水，当把一个石块浸没在水中时，水深变为6.5厘米，这个石块的体积是多少？
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">6.5 - 6</gadget>
<output>0.5</output>

<gadget id="calculator">3 * 3 * 0.5</gadget>
<output>4.5</output>

<result>4.5</result>