If the perimeter of a rectangle is 36 cm and the width is 5 cm, what is the length in cm?
长方形的周长是36厘米，宽是5厘米，则长是多少厘米．
<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">18 - 5</gadget>
<output>13</output>

<result>13</result>