A classroom is 15 meters long and 5 meters wide, and the floor is paved with square tiles with a side length of 0.5 meters. How many tiles of this kind are needed in total?
一间教室的长是15米，宽5米，用边长0.5米的正方形瓷砖铺地，共需这种瓷砖多少块？
<gadget id="calculator">0.5 * 0.5</gadget>
<output>0.25</output>

<gadget id="calculator">5 / 0.25</gadget>
<output>20</output>

<gadget id="calculator">15 * 20</gadget>
<output>300</output>

<result>300</result>