The sandpit on the school playground is a cuboid. Its length is 5 meters, its width is 4.2 meters, and its depth is 0.5 meters. How many square meters does this sandpit occupy?
学校操场的沙坑是一个长方体，它的长是5米，宽是4.2米，深0.5米，这个沙坑占地多少平方米？
<gadget id="calculator">5 * 4.2</gadget>
<output>21</output>

<result>21</result>