A rectangular nursery is 220 meters long and 50 meters longer than it is wide. What is the perimeter of the field in meters?
一块长方形的苗圃长220米，比宽长50米，这块地的周长是多少米？
<gadget id="calculator">220 - 50</gadget>
<output>170</output>

<gadget id="calculator">220 + 170</gadget>
<output>390</output>

<gadget id="calculator">390 * 2</gadget>
<output>780</output>

<result>780</result>