There are 42, 36, and 24 students in the three classes of the sixth grade to participate in the tree planting work. They should be divided into groups with equal numbers, but the students in each class cannot be disturbed. How many people can each group at most?
六年级三个班分别有42人、36人和24人参加植树劳动，要把他们分成人数相等的小组，但各班同学不能打乱，最多每组多少人？
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<result>6</result>