hey guys, im taking discrete math for the first time this semester, and all i can say is that i've been lost since the first day of class. sadly, i need this class for my major so i can't afford to fail/drop :/ I have my first quiz tommorrow and I'm 99% sure im going to fail so if you guys think you could help me out that'd be swell

the biggest problem i have with are proofs. im completely clueless in this subject. this is an example problem:

Suppose that A, B, and C are sets such that A (subset) B and B (subset) C. Show that A (subset) C.

the (subset)'s are the underlined C's but i just dont know how to put them in here. I understand that since A is a subset of B and B is a subset of C then obviously A is a subset of C. I just dont know how to prove that :\