The average of a group of numbers is defined as the sum of the values divided by the number of values. Average value= Sum of the values Number of values Example: Henry buys three items costing $2.00, $0.75, and $0.25. What is the average price? Average price= Sum of Prices = Total price = $2.00+$0.75+$0.25 Number of prices total items 3

= $3.00 = $1.00 3

If we know the average of a group of numbers in the group, we can find the sum of the numbers. It’s as if all the numbers in the group have the average value. Sum of values=average value * (times) number of values Example: The average daily temperature for the first week in January was 31 degrees. If the temperature for the first six days was 30 degrees, what was the temperature of the seventh day? The sum for all 7 days = 31x7=217 degrees The sum for the first 6 days = 30x6 = 180 degrees The temperature of the seventh day = 217 – 180 = 37 degrees