If a square lawn is increased by 2 meters, the area of the square lawn is now increased by 40 square meters compared to the original one. What is the original area of the lawn in square meters?
一块正方形草坪，将它的边长增加2米，现在正方形草坪的面积比原来增加了40平方米，原来草坪的面积是多少平方米．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">40 - 4</gadget>
<output>36</output>

<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<result>81</result>