To make a cuboid wooden box without a cover, the length is 5 decimeters, the width is 3 decimeters, and the height is 1 decimeter.
做一个不带盖的长方体木箱，长5分米，宽3分米，高1分米，至少需要多少平方分米木板．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 1 * 2</gadget>
<output>10</output>

<gadget id="calculator">3 * 1 * 2</gadget>
<output>6</output>

<gadget id="calculator">15 + 10 + 6</gadget>
<output>31</output>

<result>31</result>