Addition is just a function and functions are just sets of pairs and sets can just sit there merrily existing in the abstract without any need for time or flow or movement or such.
Time does not appear in formal logic or number theory, even though it is convenient to think of a derivation or a calculation as as sequence of steps performed one at a time.
it is also very convenient to use mathematics to model a temporal process, but we can, and often do, then show what happened (or will happen) as tables, graphs or other static representations.
I know that last sentence presupposes time, but I am not even going to attempt to rewrite it in a way that avoids doing so!