When I teach Rule 60 to my first-year Civil Procedure students, I tell them that Rule 60(a) is mainly designed to permit a court to correct clerical errors in the judgment; for example, a judgment that says that a plaintiff is entitled to "$10,000" when the jury's verdict was actually for "$100,000." Things like transcription mistakes.
Like many things, the complete truth is a little more complicated. As today's opinion from the Ninth Circuit decmonstrates.
You can in fact make lots of amendments to a judgment under Rule 60(a), including changes that arise from circumstances that are quite dissimilar to transcription errors.
It's a good opinion to read to complete your knowledge of the Federal Rules of Civil Procedure. Which is an important life objective for everyone, I'm sure.