For many Excel users functions are a very easy and fast way to build tables that without that would be hard and would take allot of time. But there is a catch... Most of them are translated from language to language. I know this might sound weird for most people who know a bit of programming, but it's true.
On the link bellow there will be a list of most of the Functions, as well as their respective translations.
If you need any explanation of any Function more deeper let me know on the comments.