With the introductory classes (math, in particular) you will find that the material is very easy. I wish I could discuss specifics, but unfortunately I can't (at least not in an open forum. PM me if you're really dying to know what they teach)
The reason for this easy introductory material is twofold.
1) It provides a uniform basis upon which all other material will be taught. Some people have either forgotten or never learned these math fundamentals and it's just a good idea to start off with the basics.
2) More importantly, it teaches you the PROCESS of how business is conducted at nuke school. There is a set method, in everything from the way you take notes to the way homework is turned in each day. It's best to get you acquainted with these practices while teaching familiar topics before moving on to the more difficult stuff.