The side length of a square floor tile is 2 decimeters, the length of the bedroom is 5 meters, and the width is 4 meters. Now, how many floor tiles are needed to lay the floor of the bedroom with this square floor tile?
正方形地砖的边长是2分米，卧室的长是5米，宽是4米，现在用这种正方形的地砖铺卧室的地面，一共需要多少块地砖？
<gadget id="calculator">0.2 / 0.2</gadget>
<output>1</output>

<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">20 / 0.04</gadget>
<output>500</output>

<result>500</result>