Xiao Ming wants to cover his room with floor tiles. The side length of the square floor tiles is 2 decimeters, the length of the room is 5 meters, and the width is 4 meters. How many square floor tiles are needed in total this time?
小明要将自己的房间巾上方地砖，方地砖的边长是2分米，房间的长是5米，宽是4米，问这次一共需要多少块方地砖？
<gadget id="calculator">4 / 0.04</gadget>
<output>100</output>

<gadget id="calculator">5 * 100</gadget>
<output>500</output>

<result>500</result>