Two identical squares are put together to form a rectangle, and the perimeter is reduced by 20 cm. What is the area of the resulting rectangle?
两个同样的正方形拼成一个长方形，周长减少了20厘米，拼成后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">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">10 * 10 * (1/50)</gadget>
<output>2</output>

<result>2</result>