Average =total sum of all the numbers / number of items in the set.
In other words, to find the average, add up all of the numbers in the set, and then divide by however many items you have.
A.
Test scores: 78,83 and 79
average =(78+83+79)/3 = 80
B.
weights : 2 lb, 5 lb, 7 lb, 5 lb, 9 lb, and 8 lb.
average = (2 lb+ 5 lb+ 7 lb+ 5 lb+ 9 lb+ +8 lb)/6 = 36/6 = 6lb
