The cross-section of a cuboid ventilation duct is a rectangle with a length of 2 decimeters and a width of 1 decimeter. The length of the duct is 2 meters. How many square meters of material are needed to make 20 such ducts?
一根长方体通风管道的横截面是一个长为2分米，宽为1分米的长方形，管道长2米，做20根这样的管道需要多少平方米材料？
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 2 * 2</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 2 * 2</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(4/5) + (2/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) * 20</gadget>
<output>24</output>

<result>24</result>