The most shameless story in the history of mathematics: Once upon a time, an old man said to his three sons before he died: I can't do it. There are only 17 horses in our family. After my death, the eldest brother will be divided into half, the second child into one third and the eldest brother into one ninth, but they will all be divided into live horses. The old man passed away. When the three brothers buried their father, they came to the stable and divided the horses according to the old man's will. They can't be separated. There's nothing they can do.

Just then, a neighbor rode by and saw their sad faces. He stepped forward and asked, What are the three brothers so worried about? The three brothers told him their father's dying orders and the difficulty of parting horses. After a little meditation, the neighbor came up with a good way to divide the horse.

Neighbors' way is to lend them one of their own horses and make 18 horses. As a result, the oldest 9 horses, the second 6 horses, the third 2 horses, and the remaining 1 horse were returned to the neighbors.

In fact, there is no answer to this question, and the above answer is wrong, which gives us an illusion.

1. According to the requirements of the topic, live horses should be divided. 17 horses cannot be divided according to the given proportions of 1/2, 1/3 and 1/6, so it is impossible to get the whole number of horses.

Secondly, we assume that we can get the number of horses with decimal points. The number of horses of the eldest brother is 8.5, that of the second brother is 5.666666, and that of the third brother is 1.888888, so there should be 17/ 18 horses. According to the neighbor's algorithm, the three brothers have more horses.

The reason is that the neighbor's horse intervened, and 17/ 18' s horse was divided by three brothers again, which obviously did not conform to the will, although the neighbor's division was an integer of the horse (PS: because according to the old man's will, the unit was 17' s horse, not 18' s horse).

There are so many contradictions, this question should be unsolvable, but this answer has been so open and popular for thousands of years that it has deceived us since primary school, and it still exists and continues to deceive our descendants.