Check this 5 min.  video clip to cardinal and ordinal numbers.

It does not, however, explain converting from a year (cardinal number) to a century (ordinal number.

Check this 2 1/2 min.  video clip about deciding in what century is a year.

Check this 8 1/2 min.  video clip about deciding in what century is a year.

After you finish taking notes and are working on your homework, if you need help, check this 6 min.  video clip I created to help you create work with years (cardinal numbers) and centuries (ordinal numbers).