The perimeter of a rectangle is 32 cm, its length is 9 cm, and its width is in cm.
一个长方形的周长是32厘米，它的长是9厘米，宽是多少厘米．
<gadget id="calculator">32 / 2</gadget>
<output>16</output>

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

<result>7</result>