Eight character passwords

How many eight character passwords are there if each character is either an uppercase letter A-Z, a lowercase letter a-z, or a digit 0-9, and where at least one character of each of the three types is used?

First how many total 8 character passwords are possible?

Second how many 8 character passwords without any digits are possible?

Third how many 8 character passwords without any lowercase letters are possible?

Finally how many 8 character passwords without any uppercase letters are possible?

The answer should be - - - ; correct?