To make a cuboid water tank with a length of 5 decimeters, a width of 3 decimeters and a height of 4 decimeters without a cover, how much iron sheet is needed at least?
做一个无盖的长5分米，宽3分米，高4分米的长方体水箱，至少需要多少铁皮？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 4 * 2</gadget>
<output>40</output>

<gadget id="calculator">3 * 4 * 2</gadget>
<output>24</output>

<gadget id="calculator">15 + 40 + 24</gadget>
<output>79</output>

<result>79</result>