An iron box without a cover is 5 decimeters long, 4.5 decimeters wide, and 2 decimeters high. How much square decimeters of iron sheet is needed to make such an iron box?
一个无盖的铁箱，长5分米，宽4.5分米，高2分米，做这样的铁箱至少需要铁皮多少平方分米？
<gadget id="calculator">5 * 4.5</gadget>
<output>22.5</output>

<gadget id="calculator">5 * 2 * 2</gadget>
<output>20</output>

<gadget id="calculator">4.5 * 2 * 2</gadget>
<output>18</output>

<gadget id="calculator">22.5 + 20 + 18</gadget>
<output>60.5</output>

<result>60.5</result>