8th grade math question help?

You Should Just Be Able To Add 189 and 577 and get 765 and then you should divide 765 by two (because you added two numbers) and get 382.5 and if you want to turn that into a fraction it would be 756/2. i Don't know if thats right but thats how i was tought to average. so you just add the numbers and divide by how many numbers there were and you get the average. i hope i helped