Obviously, a rectangle with a length of 8 cm and a width of 4 cm can be surrounded by a piece of iron wire, or it can be surrounded by a square with a side length of how many centimeters.
明明用一根铁丝围成了一个长8厘米，宽4厘米的长方形，也可以围成一个边长多少厘米的正方形．
<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<result>6</result>