To pave a rectangular floor with a length of 5 meters and a width of 4 meters, how many square floor tiles with a side length of 5 decimeters are required.
给长5米、宽4米的长方形地面铺地面砖，需要边长5分米的在正方形地面砖多少块．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 / (1/4)</gadget>
<output>80</output>

<result>80</result>