Excel formula for IF cell number is 'lower' than X, 'in between' X and Y or 'higher' Y then equals A, B, C

I can get a simple IF formula working like: =IF(A3>100,"good","bad")

but what i would like is something that works for in between theses values too.

Example:

A score of <80 = Bad, 80-100 = OK, >100 = Good Thanks.