Table of Contents### About Excel's Functions

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Functions are formulas that Excel has predefined. They're designed to take you beyond the basic arithmetic and text formulas you've seen so far. They do this in three ways:

Functions make simple but cumbersome formulas easier to use. For example, suppose that you want to add a list of 100 numbers in a column starting at cell A1 and finishing at cell A100. Even if you wanted to, you wouldn't be able to enter 100 separate additions in a cell because you would run out of room (recall that cells are limited to 255 characters). Luckily, there's an alternative: the

`SUM()`function. With this function, you would simply enter`=SUM(A1:A100)`.Functions enable you to include complex mathematical expressions in your worksheets that otherwise would be difficult or impossible to construct using simple arithmetic operators. For example, determining a mortgage payment given the principal, interest, and term is a complicated matter, at best, but you can do it with Excel's

`PMT()`function just by entering a few parameters.Functions enable you to include data in your applications that you couldn't access otherwise. For example, the

`INFO()`function can tell you how much memory is available on your system, what operating system you're using, what version number it is, and more. Similarly, the powerful`IF()`function enables you to test the contents of a cell—for example, to see whether it contains a particular value or an error—and then perform an action accordingly, depending on the result.