A bunker is 5 meters long, 4 meters wide, and 0.5 meters deep. What is the area of the bunker?
一个沙坑长5米，宽4米，深0.5米，这个沙坑的占地面积是多少．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>