Microsoft® Excel® 2010 Inside Out

Using Functions: A Preview

In simplest terms, a function is a predefined formula. Many Excel functions are shorthand versions of frequently used formulas. For example, compare =A1+A2+A3+A4+A5+A6+A7+A8+A9+A10 with =SUM(A1:A10). The SUM function makes the formula shorter, easier to read, and easier to create. Most Excel functions perform much more complex calculations, like the PMT function, which lets you calculate a loan payment at a given interest rate and principal amount.

All functions consist of a function name followed by a set of arguments enclosed in parentheses. (In the preceding example, A1:A10 is the argument in the SUM function.) If you omit a closing parenthesis when you enter a function, Excel adds the parenthesis after you press Enter—as ...