The perimeter of a rectangular vegetable field is 600 cm, its length is 230 cm, and its width is in cm.
一个长方形菜地的周长是600厘米，它的长是230厘米，宽是多少厘米．
<gadget id="calculator">600 / 2</gadget>
<output>300</output>

<gadget id="calculator">300 - 230</gadget>
<output>70</output>

<result>70</result>