Coterminal Angles Work How Again?

Ok, so let me start by saying that this is my first post here, so I am sory if I do anything wrong, or If this is not the right place to post. If so, it is entirely un-intentional and I will do whatever I can to fix this mistake.

I am 16, homeschooled, and teach myself. Most of you are probably wondering why I am not just asking my parents how coterminal angles work. Im not asking my parents, because I made a deal with them when I was 5 that I could homeschool as long as I didnt need their help.

So, now that you understand why I'm here, lets get to the question.

My understanding of coterminal angles is this:

A coterminal angles share the same terminal line.

By this defenition, each angle has infinite coterminal angles.

So if this is true, why do the practice problems only have one answer?

Thanks in advance,

Laim.