A square with a side length of 8 cm is surrounded by a piece of iron wire. If this wire is used to form a rectangle with a length of 9 cm, what is the width of this rectangle?
用一根铁丝围成一个边长为8厘米的正方形、如果将这跟铁丝围成一个长为9厘米的长方形，这个长方形的宽是多少厘米、？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">32 / 2</gadget>
<output>16</output>

<gadget id="calculator">16 - 9</gadget>
<output>7</output>

<result>7</result>