There is a rectangular piece of paper with a length of 84 cm and a width of 60 cm. If you want to cut it into several squares of the same size without any surplus, what is the longest side length of the small squares you cut out?
有一张长方形的纸，长84厘米，宽60厘米，如果要剪成若干同样大小的正方形而没有剩余，剪出的小正方形的边长最长是多少厘米？
<gadget id="calculator">2 * 2 * 3</gadget>
<output>12</output>

<result>12</result>