SUM function is one of the most used function in MS Excel. This formula not only adds user defined values in a cell but also adds values from different cells. It is used in Excel 2013, 2010, 2007 and other versions of excel with same syntax.
Formula: =SUM(5, 5) or =SUM(A1, B1) or =SUM(A1:B5)
The SUM formula does exactly what you would expect. It allows you to add 2 or more numbers together. You can use cell references as well in this formula.
The above shows you different examples. You can have numbers in there separated by commas and it will add them together for you, you can have cell references and as long as there are numbers in those cells it will add them together for you, or you can have a range of cells with a colon in between the 2 cells, and it will add the numbers in all the cells in the range.