There is a rectangular parallelepiped glass jar with a length of 5dm, a width of 4dm, and a depth of 2dm. Put a cube iron block into the jar. Then fill it with water (the water has submerged the cube iron block at this time), when the iron block is taken out, the water level drops by 0.2dm, what is the volume of this iron block?
有一个长5dm，宽4dm，深2dm的长方体玻璃缸，向缸中放入一个正方体铁块．然后注满水(此时水已淹没正方体铁块)，当取出这个铁块后，水面下降了0.2dm，这个铁块的体积是多少？
<gadget id="calculator">5 * 4 * 0.2</gadget>
<output>4</output>

<result>4</result>