Even with all the context you suggested, the problem statement is just not very clear, and, in computing, computer science, and software, that lack of clarity is not a small point.
Put more bluntly, there is no excuse, and in serious software, especially for embedded systems, there is no role, for abbreviations that are on or over the line into gibberish. You are correct that such gibberish is common in software; my point is that we should not do that and should object.
Yes, in my suggested problem statement, I used notation common in mathematics. Still, the math community still says that such writing is English. GOOD.
Here is a big point: Computer science, computing, and software have no good substitute for such use of how mathematics is written. There is a partial substitute in practice if assume a particular programming language.
The error of n instead of -n or the absolute value of n is small but is an example of a huge point: A subroutine needs a description. A subroutine is precisely something and should have a precise description. The problem here is so simple we can get by with being imprecise as you suggest, but computing is not limited to such simple routines, and the complicated ones also need precise descriptions. Net, we need to write precise descriptions. Knuth did this in TACP (yes, I abbreviate!); it really is possible.
For assuming that 'add1' means an argument 1 passed to a function add is asking a lot even just in the context of software.
In passing a constant to a function there will be the issue, that should be addressed, of passing 'by value' or 'by reference'. In Fortran a constant is passed by reference with all the problems, side effects, and surprises there unto appertaining! We can't yet assume that Fortran is buried!
If my work does well and I start to hire, I will give a lot of weight to people who are good at reading and writing technical material and will prefer that they know how to read and write abstract math. For learning Visual Basic .NET, a book of code samples and a one week class should be able to do a lot. Net, I'm questioning if I should require new hires for programming to know any 'computing' at all.