The length of a rectangle is 20 decimeters, which is 5 decimeters more than its width, what is its perimeter?
长方形的长是20分米，比宽多5分米，它的周长是多少分米
<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<gadget id="calculator">20 + 15</gadget>
<output>35</output>

<gadget id="calculator">35 * 2</gadget>
<output>70</output>

<result>70</result>