Use square floor tiles with a side length of 40 cm to pave a sidewalk with a length of 18 meters and a width of 4 meters. At least how many such bricks are needed?
用边长40厘米的正方形地砖铺一段长为18米，宽为4米的人行道，至少需要多少块这样的砖？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) * (2/5)</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">4 / (4/25)</gadget>
<output>25</output>

<gadget id="calculator">18 * 25</gadget>
<output>450</output>

<result>450</result>