In most programming languages, the statement

`n = n + 1`

is perfectly valid. It simply increments

`n,`

by 1 (of course, you may prefer

`n++`

).

When I was doing GCSE maths I had a homework involving prime numbers.
I wrote a program which checked a sequence of numbers - from 1 up to a specified limit - and output their factors. My code (written in BASIC) contained at least one iterative loop, inside one of which I incremented n by 1

`n = n + 1`

Now my maths teacher had never seen 'programming' before.
I - assuming this line was fairly self explanatory - had neglected to furnish it with a comment explaining what it did.
As a result, when I got the marked homework back again, I saw red scribble around the line, and the remark

__How__ can n = n + 1? See me.

Despite trying to explain to her that

*this statement is *__not__ "wrong", it just increments n by 1, I was unable to persuade her not to drop my mark.

I never even thought of trying to prove that n = n + 1.