After the side length of a square is increased by 2 cm, the perimeter of the large square obtained is 56 cm. Find the side length of the original square. (Solution of column equation)
一个正方形的边长增加2厘米后，得到的大正方形的周长是56厘米，求原来正方形的边长．(列方程解)
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">56 - 8</gadget>
<output>48</output>

<gadget id="calculator">48 / 4</gadget>
<output>12</output>

<result>12</result>