How many factors of $2010^{2010}$ have last digit $2$?
It is not difficult to solve this using python/mathematica, but I want to know how to (smartly) solve this one with paper and pencil?
How many factors of $2010^{2010}$ have last digit $2$?
It is not difficult to solve this using python/mathematica, but I want to know how to (smartly) solve this one with paper and pencil?