The largest freshwater lake in my country - Poyang Lake has an area of 3960 square kilometers. The second largest freshwater lake, Dongting Lake, has an area of 1100 square kilometers more than that of Poyang Lake (1/3). What is the area of Dongting Lake in square kilometers ?
我国最大的淡水湖--鄱阳湖的面积是3960平方千米，第二大淡水湖洞庭湖的面积比鄱阳湖的(1/3)多1100平方千米，洞庭湖的面积是多少平方千米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3_960 * (1/3)</gadget>
<output>1_320</output>

<gadget id="calculator">1_320 + 1_100</gadget>
<output>2_420</output>

<result>2_420</result>