The living room of Xiaoming’s house is square, and it takes exactly 400 pieces to pave the floor with square bricks with a side length of 0.4m.
小明家的客厅是正方形，用边长0.4m的方砖铺地正好需要400块，如果改用边长0.8m的方砖铺地，需要多少块？
<gadget id="calculator">0.8 * 0.8</gadget>
<output>0.64</output>

<gadget id="calculator">400 / 0.64</gadget>
<output>625</output>

<gadget id="calculator">0.4 * 0.4 * 625</gadget>
<output>100</output>

<result>100</result>