There are two big and small squares, the side length of the big square is 1 cm less than twice the side length of the small square, and their perimeters differ by 24 cm, what is the area of the big square in square centimeters?
大、小两个正方形，大正方形的边长比小正方形边长的2倍少1厘米，而它们的周长相差24厘米，则大正方形的面积是多少平方厘米．
<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">14 - 1</gadget>
<output>13</output>

<gadget id="calculator">13 * 13</gadget>
<output>169</output>

<result>169</result>