The ratio of length to width of a rectangle is 5:1. If the length is reduced by 8 cm and the width is increased by 12 cm, it becomes a square. What is the area of the original rectangle?
一个长方形长与宽的比是5：1，如果长减少8厘米，宽增加12厘米，就变成了一个正方形．原来长方形的面积是多少平方厘米？
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 5 * 5</gadget>
<output>125</output>

<result>125</result>