# Working with Formulas and Functions in Excel 2010

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This chapter is from the book

## Using Nested Functions

A nested function uses a function as one of the arguments. Excel allows you to nest up to 64 levels of functions. Users typically create nested functions as part of a conditional formula. For example, IF(AVERAGE(B2:B10)>100,SUM(C2:G10),0). The AVERAGE and SUM functions are nested within the IF function. The structure of the IF function is IF(condition_test, if_true, if_false). You can use the AND, OR, NOT, and IF functions to create conditional formulas. When you create a nested formula, it can be difficult to understand how Excel performs the calculations. You can use the Evaluate Formula dialog box to help you evaluate parts of a nested formula one step at a time.

Create a Conditional Formula Using a Nested Function

• Click the cell where you want to enter the function.
• Click the Formulas tab.
• Type = (an equal sign).
• Click a button from the Function Library with the type of function you want to use, click a submenu if necessary, and then click the function you want to insert into a formula.

For example, click the Logical & Reference button, and then click COUNTIF.

Excel inserts the function you selected into the formula bar with a set of parenthesis, and opens the Function Arguments dialog box.

• Type a function as an argument to create a nested function, or a regular argument.

For example, =COUNTIF(E6:E19), “>”&AVERAGE(E6:E19)).

• Click OK.

Evaluate a Nested Formula One Step at a Time

• Select the cell with the nested formula you want to evaluate. You can only evaluate one cell at a time.
• Click the Formulas tab.
• Click the Evaluate Formula button.
• Click Evaluate to examine the value of the underlined reference.

The result of the evaluation appears in italics.

• If the underlined part of the formula is a reference to another formula, click Step In to display the other formula in the Evaluation box.

The Step In button is not available for a reference the second time the reference appears in the formula, or if the formula refers to a cell in a separate workbook.

• Continue until each part of the formula has been evaluated, and then click Close.
• To see the evaluation again, click Restart.

Some parts of formulas that use IF and CHOOSE functions are not evaluated, and #NA is displayed. If a reference is blank, a zero value (0) is displayed.