To make a cuboid iron chimney, each section is 2 decimeters long, 4 decimeters wide, and 0.5 meters high, how many square meters of iron sheets should be used at least?
要制作一个长方体的铁皮烟囱，每节长2分米，宽4分米，高0.5米，至少要用多少平方米的铁皮？
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">2 * 0.5 * 10</gadget>
<output>10</output>

<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<gadget id="calculator">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">18 * (1/50)</gadget>
<output>9/25 = around 0.36</output>

<result>9/25 = around 0.36</result>