choosing first year computing classes?

Hello, I am a first-year computing student and I am struggling to pick my courses I am taking CIS 121 but I have no clue what the difference is between taking that one and the 110, Secondly, I am thinking of taking Math 110 I think I am pretty good at math it's just my calc teacher didn't teach us much and I went out with almost no knowledge in the class so I would have to start from the beginning. To which taking it means I don't have to take CISC 102. And I have no clue what the difference between Math 121 and Math 120 is. And if I take Math 110 what will I do with the extra spot since I don't have to take CISC 102? I am so lost and confused is there anyone that can help me?