To thank her five volunteers, Mai gave each of them the same number of stickers. Then she gave them each two more stickers. Altogether, she gave them a total of 30 stickers.
If Mai gave each volunteer the same number of stickers initially, then the total number of stickers she gave out without the additional two stickers would be 30 - (5 * 2) = 30 - 10 = 20 stickers.
Thus, each volunteer initially received 20 / 5 = 4 stickers.
Therefore, Mai gave each volunteer 4 initial stickers and then an additional 2 stickers, totaling 6 stickers each.