If the length of a rectangular wooden board is reduced by 4 decimeters, then its area will be reduced by 24 square decimeters. At this time, the remaining part is exactly a square. How many square decimeters is the area of the original rectangle?
一个长方形的木板，如果长减少4分米，那么它的面积就减少24平方分米，这时剩下的部分恰好是一个正方形，那么原来长方形的面积是多少平方分米？
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 6</gadget>
<output>60</output>

<result>60</result>