7. (10 points) There is a magical tree with 58 fruits on it. On the first day, 1 fruit will fall from the tree. Starting from the second day, the number of fruits that fall each day is 1 more than the previous day. However, if the number of fruits on the tree is less than the number that should fall on a certain day, then on that day it will start over by dropping 1 fruit and continue according to the original rule. This continues. On the $\qquad$th day, all the fruits on the tree will have fallen.
【Solution】Solution: According to the problem, we have:
$$
1+2+3+4+5+6+7+8+9+10=55 \text {. }
$$

On the eleventh day, since there are not 11, it can only start from 1 again, and then drop 2, which makes it exactly:
$$
1+2+3+4+5+6+7+8+9+10+1+2=58 \text {. }
$$

In total, it is 12 days.
Therefore, the answer is: 12