Finding a mathematical average requires totaling the items in a series and dividing the total by the number of items. For instance, to find the average of 5, 10 and 3, add the numbers to get 18 and divide by 3. Use this formula to find information for such items as the average salary for a job, number of apples in a pound, age of a certain group or height of cupboards in a house.
This formula works to find the basic mathematical average of any group of numbers. To find the average, add the numbers and divide by how many numbers you used. For instance, to find the average of grades in a class, add all of the grades and divide by the number of grades. If you received a 95, 80, 85 and 100 on four exams, add the numbers to yield 360 and then divide by 4 to find the average of 90.
