Welcome to the boards!
Microbiology is DEFINITELY important in nursing. Learning all about bacteria and virus biology is necessary to understand the infection process. In a way, microbiology teaches you to RESPECT these "bugs" which will be important later on. Infection is a nasty thing, and this class covers it all. Labs are great here too, everything from swabbing your pencil to find out what nasties are growing on it, to placing tiny bits on antibiotics in "infected" petri dishes and actually SEEING which ones kill what baceria. It was truly fascinating! As far as everyday use, I understand which "bugs" are worse than others, which antibiotics will probably be ordered, etc. The most IMPORTANT thing you take from microbiology and use in everyday nursing is the need for cleanliness and HANDWASHING!!!
Chemistry...eh...hated it! I still don't really understand why it was so important, but you deal with chemicals during your career as a nurse so you at least need a gereral course during college. At my school we got to take an easy chemistry class but now I hear they are making everyone take organic chemistry. In everyday use, it really only gives you a familiarity with the minerals, electrolytes, and oxygen, things like that. It may also help later on when working with IV solutions of different types.
As far as math courses...there was really no math required in college so long as you already had taken things like algebra. Statistics was the only math course I did in college, and that isn't so much math as a horrible entity unto itself! You need statistics to understand research studies, and to prepare you in case you plan to go on for post-graduate degrees.
Now, math on the job is just basic calculations - WITH a calculator! You learn formulas for figuring out medication dosages and IV drips, things like that. In peds/neo you probably do more calculations because there are very few standard doses -almost everything has to be figured by the kiddo's weight.
In most nursing schools, you'll have to take the above classes, plus pharmacology, nutrition, and pathophysiology (where you learn about how disease alters the function of the body organs and systems).