1-6 Simple draw.

Six students with the number of 1 ~ 6 are ranked to the target position of 1 ~ 6, and all the ranking methods are A66=720.

It happened that three students got the same target position number as their own, and the arrangement was 2C63=40.

So just three students have the same number of goals as theirs, and the probability P=40720= 1 18.

So the answer is 1 18.