A rectangle whose length is shortened by 4 decimeters becomes a square with an area of 64 square decimeters. What is the area of the original rectangle?
一个长方形，将长缩短了4分米，变成了面积是64平方分米的正方形，原来的长方形的面积是多少平方分米．
<gadget id="calculator">8 * 8</gadget>
<output>64</output>

<result>64</result>