A rectangle with a length of 6 cm and a width of 4 cm is surrounded by wire. How long is the wire at least?
用铁丝围一个长6厘米，宽4厘米的长方形．至少要用多长的铁丝？
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>