In principle terminology questions are ontopic. The question as is strikes me as slightly vague.
"Long addition" is a term that I think is used for the specific calculation. Thus it may be this. "Long multiplication" is quite common for multiplication. If you want a shared term I would not know, but invoking the other terms might help to sharpen the question.
In any case "as is" I would not know if "long addition" would satisfy you as an answer.
Furthermore, "best" is usually not a good word to use, especially not without further qualification. It does make a difference if you search a term to use for students or if you are writing a scholarly article for a pedagogical journal.
Or, somebody might think X is best while nobody uses it and Y is common. What then? Do you answer X or Y? Alright if it is as clear cut one could say both, but again it adds ambiguity to the question.
Thus, I recommend to clarify the question before asking.