6. (10 points) There is a magical tree with 46 fruits on it. On the first day, 1 fruit will fall from the tree, and 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 until all the fruits on the tree have fallen.

如此继续, 那么第天树上的果子会都掉光.

So it continues, until all the fruits on the tree have fallen.
6. (10 points) There is a magical tree with 46 fruits on it. On the first day, 1 fruit will fall from the tree, and 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 that day it will start over by dropping 1 fruit and continue according to the original rule. This continues, so by the 10th day, all the fruits on the tree will have fallen.
【Solution】Since $1+2+3+4+5+6+7+8+9=45$ (fruits)
By the tenth day, it is not enough to start over and drop 1 fruit. It ends exactly then.
$$
45+1=46 \text { (fruits) }
$$

Therefore, the answer is: 10