Uncle Li surrounded a rectangular vegetable field with a 640-meter fence. If the length of this vegetable field is 190 meters, what is the width in meters?
李大伯用640米的篱笆围了一块长方形的菜地．如果这块菜地的长是190米，那么宽是多少米．
<gadget id="calculator">640 / 2</gadget>
<output>320</output>

<gadget id="calculator">320 - 190</gadget>
<output>130</output>

<result>130</result>