The SUM function, one of the math and trig functions, adds values. You can add individual values, cell references or ranges or a mix of all three.
Returns the average (arithmetic mean) of the arguments. For example, if the range A1:A20 contains numbers, the formula =AVERAGE(A1:A20) returns the average of those numbers.
AVERAGE(number1, [number2], …)
The AVERAGE function syntax has the following arguments:
Number1 Required. The first number, cell reference, or range for which you want the average.
Number2, … Optional. Additional numbers, cell references or ranges for which you want the average, up to a maximum of 255