A rectangular parallelepiped glass cylinder measures 5 decimeters long and 3 decimeters wide from the inside. The depth of the existing water is 1.5 decimeters. When a stone is submerged in the water, the depth of the water is 2 decimeters. Ask this stone What is the volume of cubic decimeters?
一个长方体玻璃缸，从里面量长5分米，宽3分米，现有水的深度是1.5分米，当把一个石块浸没在水中时，水的深度为2分米，问这个石块的体积是多少立方分米？
<gadget id="calculator">2 - 1.5</gadget>
<output>0.5</output>

<gadget id="calculator">5 * 3 * 0.5</gadget>
<output>7.5</output>

<result>7.5</result>