classroom is 15 meters long and 6 meters wide. If floor tiles with an area of 20 square decimeters are used to pave the floor, how many such floor tiles are needed?
一间教室长15米，宽6米，如果用面积为20平方分米的地砖铺地，需要这样的地砖多少块？
<gadget id="calculator">100 / 20</gadget>
<output>5</output>

<gadget id="calculator">15 * 6 * 5</gadget>
<output>450</output>

<result>450</result>