A piece of iron wire forms a rectangle whose length is 6 cm and width is 5 cm. If this wire forms a square with a side length of 4 cm, how many centimeters are left?
一根铁丝围成一个长方形，它的长是6厘米，宽是5厘米，如果用这根铁丝围成一个边长为4厘米的正方形，还剩多少厘米？
<gadget id="calculator">6 + 5</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">22 - 16</gadget>
<output>6</output>

<result>6</result>