Use square bricks with a side length of 40cm to pave a section of sidewalk with a length of 20m and a width of 80cm. How many such square bricks are needed at least?
用边长40cm的正方形方砖铺一段长20m，宽80cm的人行道路面，至少需要多少块这样的方砖？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<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">(4/5) / (4/25)</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>