Xiao Ming will make a rectangular wire frame with a length of 2.8 decimeters and a width of 1.2 decimeters. How many decimeters of iron wire does Xiao Ming need to buy at least?
小明要做一个长是2.8分米，宽是1.2分米的长方形铁丝框架．小明至少要买多少分米铁丝．
<gadget id="calculator">2.8 + 1.2</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>