rectangular vegetable field against a wall is 8 meters long and 5 meters wide. To surround the vegetable field with a fence, what is the minimum length of the fence?
一块靠墙的长方形菜地，长8米，宽5米，要给菜地围上篱笆，篱笆至少长多少米？
<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>