A rectangular vegetable field is 9 meters wide and three times as long as it is wide. Walk around the edge of the vegetable field, how many meters have you walked?
一块长方形菜地，宽是9米，长是宽的3倍．沿着菜地的边走一圈，走了多少米？
<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">27 + 9</gadget>
<output>36</output>

<gadget id="calculator">2 * 36</gadget>
<output>72</output>

<result>72</result>