[nie]

> What am I doing wrong?

I don't think you are doing anything wrong. Depending on how the book is written, some might be really boring and unchallenging, pick another one! If you are looking for brain-wrecking adventure and some good story telling, pick something that starts with number theory. If you are looking for understanding the bread and butter for most recent big discoveries and theory crafting, pick something that focus on Complex Analaysis, High dimensional calculus or partial differential equations. If you are planning to stick in the field of computer science for good, pick something that focus on abstract algebra _and_ probabilty theory.

> I often get bored because I don't see the usage in my real life coding.

Then you don't need mathmatics. Depending what you do in coding, there is really rare type of work that need mathematics. Sciences and Mathematics are so far from practical use they are there purely for the sake of knowledge. This isn't just you, it's the case for everyone. Unless some day you find the interest to battle that boredom, the probability of you finding some usage from mathematics might be very unlikely.