To pave the floor with square bricks, if you use square bricks with a side length of 5dm, you need 400 pieces. If you use square bricks with a side length of 4dm instead, how many square bricks are needed?
用方砖铺地，如果用边长是5dm的方砖来铺，需要400块．如果改用边长是4dm的方砖来铺，需要方砖多少块？
<gadget id="calculator">5 * 5 * 400</gadget>
<output>10_000</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">10_000 / 16</gadget>
<output>625</output>

<result>625</result>