A rectangle whose length increases by 1/4 and width decreases by 1/5 has an area of 80 square centimeters. What is the area of the rectangle in square centimeters?
一个长方形，长增加(1/4)，宽减少(1/5)后，面积是80平方厘米．这个长方形原来的面积是多少平方厘米．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 100</gadget>
<output>80</output>

<result>80</result>