Dig a cuboid pool with a length of 5m, a width of 4m, and a depth of 2.5m. What is the minimum floor area of this pool?
挖一个长5m、宽4米、深2.5m的长方体水池，这个水池的占地面积至少是多少．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>