The floor of the classroom is just covered with 500 square bricks with an area of 9 square decimeters. If it is paved with square bricks with a side length of 5 decimeters, how many bricks are needed?
教室地面用面积为9平方分米的方砖500块正好铺满，如果改用边长为5分米的方砖铺，需要多少块？
<gadget id="calculator">9 * 500</gadget>
<output>4_500</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">4_500 / 25</gadget>
<output>180</output>

<result>180</result>