A cube fish tank with a side length of 30 cm, the height of the existing water is 20 cm, now put stones to make it completely submerged, and the water level rises to 25 cm, how many cubic centimeters are the stones put in?
一个棱长为30厘米的正方体鱼缸，已有水的高度是20厘米，现在放入石头，使其全部浸没，水面升高到25厘米，放入的石头是多少立方厘米？
<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">30 * 30 * 5</gadget>
<output>4_500</output>

<result>4_500</result>