If the width of a rectangle is increased by 2 decimeters, the area will increase by 20 decimeters square. At this time, it is just a square. What is the area of the original rectangle?
一个长方形的宽增加2分米后，面积就增加20平方分米，这时正好是个正方形，原来长方形的面积是多少平方分米．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<result>80</result>