For a classroom, 500 square bricks with an area of 9 square decimeters are exactly paved. If you use square bricks with a side length of 5 decimeters, how many pieces are needed?
一间教室，用面积9平方分米的方砖，500块正好铺完．如果用边长5分米的方砖，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>