rectangular piece of paper with a length of 18 cm and a width of 12 cm should be divided into small squares of equal size without any residue. What is the maximum length of the side of the square in centimeters.
一张长18厘米，宽12厘米的长方形纸，要分成大小相等的小正方形，且没有剩余．正方形的边长至多是多少厘米．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<result>6</result>