A rectangular container is 5 decimeters long, 3 decimeters wide, and 4 decimeters high. The original water depth is 2 decimeters. After putting a piece of iron, the water rises to 3.5 decimeters. What is the volume of this piece of iron?
一个长方形容器，长5分米，宽3分米，高4分米，原水深2分米，放入一块铁后，水升高到3.5分米，这块铁块的体积是多少？
<gadget id="calculator">3.5 - 2</gadget>
<output>1.5</output>

<gadget id="calculator">5 * 3 * 1.5</gadget>
<output>22.5</output>

<result>22.5</result>