Aha! It seems you are now working on absolute value. If you don't know what that is, I'll give you a teeny lesson. :)
|2 - 2| = 0
2 - 2 = 0
|-1 - 4| = 5
-1 - 4 = -5
|-100 - 1| = 101
-100 - 1 = -101
So basically the absolute value signs get rid of the negative number after the equation has been solved. There is no such thing as "negative" in absolute value!
The distance between H and K is 9/4. Remember, this line is flat, so you are not going to be getting any negative numbers as a result. It's absolute value.
K = 7/4, or 7/4 points away from 0.
------|--------------------------|----
K 9/4 distance H
7/4 + 9/4 = 16/4, 16/4 = 4. H = 4 :)
Let me know if you need any examples. Hope this helps!