SUM
Adds up numbers or values in cells / ranges
Syntax of SUM formula:
=SUM(number1, [number2], …)
In words:
=Determine the sum of(this number, [this number also], and any other number mentioned…)
Examples of Excel Sum Formula:
=SUM(6+7+8) will return 21
=SUM(A3:B7) will sum the numeric values in range A3:B7.