The perimeter of a rectangle is 48 cm, the length is 18 cm, and the width is in cm.
一个长方形周长是48厘米，长是18厘米，宽是多少厘米．
<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<gadget id="calculator">24 - 18</gadget>
<output>6</output>

<result>6</result>