The SUM function is most often used to add rows or columns of numbers in an Excel worksheet
Individual values can also be summed. In this situation, each number or cell reference is separated from the other data by a comma " , "
As can be seen in the image to the right, the function ignores empty cells in the range along with any text data and logical values.
Location in Excel
All functions in Excel can be found under the Formulas tab of the ribbon. The SUM function is located in the Math & Trig Function Group
More information: Excel SUM Function Tutorial