For a hall, it takes 324 bricks to pave the floor with square bricks with a side length of 0.4 meters.
一间大厅，用边长0.4米的方砖铺地，需用324块，若改铺边长0.3米的方砖，需要多用几块？
<gadget id="calculator">0.4 * 0.4 * 324</gadget>
<output>51.84</output>

<gadget id="calculator">0.3 * 0.3</gadget>
<output>0.09</output>

<gadget id="calculator">51.84 / 0.09</gadget>
<output>576</output>

<gadget id="calculator">576 - 324</gadget>
<output>252</output>

<result>252</result>