This is the sum the numbers in a set, divided by the number of items in the set. example: for example, this of the set {2,4,6,8,10) is equal to (2+4+6+8+10)/5 = 6.

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.