In the barbecue restaurant, there is a cuboid range hood with a length of 10 meters, a width of 0.5 meters, and a height of 0.4 meters. How many square meters of iron sheets are needed to make such a range hood?
在烧烤店内，有一个长10米、宽0.5米，高0.4米的长方体抽油烟管，制作一个这样的抽油烟管需要多少平方米的铁皮？
<gadget id="calculator">10 * 0.5</gadget>
<output>5</output>

<gadget id="calculator">10 * 0.4</gadget>
<output>4</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>