Use cardboard to make a cuboid box with a length of 6 decimeters, a width of 40 centimeters, and a height of 3 decimeters. How much cardboard is needed at least?
用硬纸板做一个长方体盒子，长6分米，宽40厘米，高3分米，至少需要多少硬纸板？
<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">24 + 18 + 12</gadget>
<output>54</output>

<gadget id="calculator">54 * 2</gadget>
<output>108</output>

<result>108</result>