A rectangle has a perimeter of 36 meters, a length of 10 meters, and a width of 10 meters.
一个长方形的周长是36米，长是10米，宽是多少米．
<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">18 - 10</gadget>
<output>8</output>

<result>8</result>