Definition of “plus” - Learner’s Dictionary

plus

preposition us uk /plʌs/
Extra Examples
Two plus two equals four.What's eleven plus nine?Ten plus four is fourteen.Four plus three is seven.Nine plus nine is eighteen.
ADDED

A2 added to:

Five plus three is eight.
AND

B1 and also:

You've won their latest CD plus two tickets for their concert.

(Definition of “plus preposition” from the Cambridge Learner's Dictionary © Cambridge University Press)