There is a square lotus pond in the garden. Its circumference is 640 decimeters, what is its area in square meters?
花园里有一个正方形的荷花池．它的周长是640分米，面积是多少平方米？
<gadget id="calculator">640 / 4</gadget>
<output>160</output>

<gadget id="calculator">640 / 4 / 100</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">160 * (8/5)</gadget>
<output>256</output>

<result>256</result>