A rectangle with a perimeter of 80 cm has a length of 28 cm and a width of 28 cm?
周长是80厘米的长方形，它的长是28厘米，宽是多少厘米？
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<gadget id="calculator">40 - 28</gadget>
<output>12</output>

<result>12</result>