Uncle Li surrounded a rectangular vegetable field with a 64-meter-long fence. If the length of this vegetable field is 19 meters, what is its width? (solution by equation)
李大伯用64米长的篱笆围了一块长方形的菜地．如果这块菜地的长是19米，那么它的宽是多少米？(用方程解)
<gadget id="calculator">64 / 2</gadget>
<output>32</output>

<gadget id="calculator">32 - 19</gadget>
<output>13</output>

<result>13</result>