If the length of the rectangle is reduced by 5cm, the area will be reduced by 40cm**2. What is left is exactly a square, what is the area of the original rectangle?
长方形的长如果减少5cm，面积就减少40cm**2．剩下的恰好是个正方形，原长方形的面积是多少平方厘米？
<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 8</gadget>
<output>104</output>

<result>104</result>