Functions are another form super-variable, as it were, where you do a bunch of work that is assigned to something you can print out. But in this case you aren't injecting a bunch of CSS, instead you are just printing out a nice, final value. For many things you will want to do with functions, someone else has probably already written it. Sass comes with a lot of predefined functions for you to use, and there are libraries, like Compass, which provide many more. We'll take a look at some of the functions that Sass provides for us and see a function in action, along with our mixin, side by side, to really see the difference between them.
This video is archived and won't be updated. We're keeping it online for now as a courtesy.