Syntax. SUM(number1,number2,...)
Definition. This function adds all numbers specified as arguments.
Arguments
number1 (required) and number2 (optional) The minimum number of values is 1, and the maximum is 255 (30 in Excel 2003 and earlier versions) that you want to add (but a second value makes sense for a sum). Instead of separate numbers, it is also possible to build a sum for a range of cells—for example, A1:A5.
Background. The result of an addition operation is called the sum. The sign for addition is the plus sign (+), but the Σ is also used:
x = a + b + c + d + ...
or
x = Σ(a, b, c, d...)
The arguments for the SUM() function can be numbers, logical values, and numerals when directly entered in the formula. For example:
The logical value TRUE is converted to 1.
“12” is treated as 12 even though the value is enclosed in quotation marks.
If an argument is an array or a reference, only the numbers in that array or reference are counted. Empty cells, logical values, or text in the array or reference are ignored.
Arguments that are error values or text that cannot be converted into numbers cause errors.
Example. There are so many practical uses that Excel provides the Σ symbol in the start bar as well as in the function bar. No Excel user wants to do without this function; for example, to add expenses: =SUM(3.25,5.30,4.70) returns 13.25.
More examples:
=SUM(1,4,7) returns 12.
=SUM(A2:B5) adds the values in cell range A2:B5.
=SUM(A2:B5,12) adds 12 to the sum of cell range A2:B5.