It takes 500 pieces to pave the floor with square bricks with a side length of 3 decimeters; how many pieces are needed to pave the same floor with rectangular bricks with a length of 5 decimeters and a width of 3 decimeters?
用边长为3分米的正方形砖铺地，需500块；现在改用长5分米，宽3分米的长方形砖铺同一块地，需要多少块？
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">9 / 15</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">500 * (3/5)</gadget>
<output>300</output>

<result>300</result>