In This Chapter
Finding how the Logical functions operate
Using Logical functions to create decision-making formulas
Using Logical functions to create formulas that trap errors
The Logical function category is a small but powerful group of six functions (TRUE, FALSE, IF, AND, OR, and NOT) that you can use in decision-making formulas. (A decision-making formula is one where one set of values should be used or action taken when a particular condition is met and another when it is not.) You can also combine them with certain Information functions (such as ISBLANK, ISNUMBER, ISTEXT, and ISERROR) to create error-trapping formulas that prevent Excel error values (especially #DIV/0!, #NUM!, and #VALUE! errors) from spreading to other dependent formulas in the spreadsheet.
In this chapter, you get a chance to practice using the Logical functions in spreadsheets to create both decision-making and error-trapping formulas.
The Logical functions, as their name implies, deal exclusively with the Logical values of TRUE and FALSE. With the exception of the TRUE, FALSE, and NOT functions (whose only purpose is to enter the Logical values, TRUE, FALSE, and its opposite into a cell of the worksheet), the other three Logical functions, IF, AND, and OR, evaluate expressions entered as their arguments as either TRUE or FALSE.
The granddaddy of all the Logical functions is the IF function, which follows this syntax: