How do you find an average of a group of numbers?

Add them together and divide it by the amount of the numbers you added e.g. average of 34, 72, 63, 81 = 34 + 72 = 106, 63 + 71 =134, 134 + 106 = 240. 250 divided by 4 is 60 so therefore 60 is the average.