To make a cuboid ventilating pipe with a cross-section length of 3 decimeters, width of 2 decimeters, and length of 4 meters, how many square meters of iron sheets are needed at least?
要制作1根横截面长3分米，宽2分米，长4米的长方体通风管，至少需要多少平方米的铁皮？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 4</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 4</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(6/5) + (4/5)</gadget>
<output>2</output>

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

<result>4</result>