Uncle Wang surrounded a rectangular vegetable field with a 56-meter-long fence. If the width of the field is 12 meters, what is the length in meters?
王叔叔用56米长的篱笆围了一块长方形的菜地．如果这块地的宽是12米，那么长是多少米？
<gadget id="calculator">56 / 2</gadget>
<output>28</output>

<gadget id="calculator">28 - 12</gadget>
<output>16</output>

<result>16</result>