These Tutorials (many of which are interactive) are to help with the math used in Chemistry:

Significant Figures                                                average atomic mass calculations
Nomenclature (interactive)                                  gas laws
Interactive electron configuration practice        pH calculations practice
bonding explanation by analogy
more interactive naming practice
interactive balancing chemical equations
mole quiz
Empirical Formula
molecular formula

Test Banks
basics of chemistry

Great group of tutorials and practice by subject:
ChemTeam