Cut a rectangular board with a length of 18 cm and a width of 12 cm into a square (just divided), what is the maximum side length of this square?
把一块长18cm，宽12cm的长方形木板割成正方形(刚好分完)，这个正方形的边长最大是多少．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<result>6</result>