A rectangle with a perimeter of 24 cm has a length of 8 cm and a width of 8 cm.
周长是24厘米的长方形，长是8厘米，宽是多少厘米．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<result>4</result>