It could be the value of a function
d(x) when d=4. It could also indicate a section from a legal document, such as the Federal Register, or the Internal Revenue wealth category 401(k), or a type of nontaxable charity like 501(c). It could be lots of things. It could be a line from a Federal Tax form. We'd need to know the context.
What does d(4) mean? What is it?
2 answers
It has something to do with functions. We are working on this in a 9th grade ACC Math class