A coin is flipped n-times (even). The expected number of Heads is n/2.?

Maybe you had better re-learn what the word "likelihood" means. Maybe you would better understand it if we used the word PROBABILITY? There are only two possible outcomes of flilpping the coin - heads or tails, so the probability of it coming up heads is 1/2, so as long as the probability holds (which it will under the "laws") then if you counted how many times you flipped it Ii.e., "n"), the number of "heads" you got would be half that number, or n/2