I don't really understand what you're asking. Is there a specific question that you need to know this "process" for?
Say i have a value n, and in a formula i want to represent that n is the number of stuff from t=0 to t=5s. Example: x=y/n(from t=0 - t=5)
This might be a stupid question but I cant figure out how to properly notate it in a formula :P