A square iron frame is made from a rectangular iron frame with a length of 5 cm and a width of 3 cm. What is the perimeter of the square iron frame in cm?
把一个长为5厘米，宽为3厘米的长方形铁框做一个正方形铁框，这个正方形铁框的周长是多少厘米．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>