A cube glass fish tank, the bottom side is 5 decimeters long, and the water level rises by 0.5 decimeters after a stone is put in. What is the volume of the stone?
一个正方体玻璃鱼缸，底面边长5分米，放入一块石头后水面升高了0.5分米，这块石头的体积是多少．
<gadget id="calculator">5 * 5 * 0.5</gadget>
<output>12.5</output>

<result>12.5</result>