Set Predefined or Custom Formulas
You can set custom formulas using the Define Custom Formula icon.
The following illustration shows the Define Custom Formula icon.
The Formula group of commands is available from the following tabs:

Column tab

Total Cell tab

Chart Measure Field tab

Pivot Table Data tab
Note that not all options are applicable to each component type.
About the Predefined Formulas
The table provides definitions of predefined formulas.
The menu provides the predefined formulas that are described in the following table.
Formula  Description 

No Formula 
Removes any mathematical formula from a numeric column. 
Blank Text 
Removes all data and inserts blank text. 
Count 
Returns the count of the number of occurrences of the element in the current group. 
Count Distinct 
Returns a count of the distinct values of an element in the current group. 
Summation 
Sums the values of the element in the current group. 
Average 
Displays the average of the values in the current group. 
Maximum 
Displays the highest value of all occurrences in the current group. 
Minimum 
Displays the lowest value of all occurrences in the current group. 
For nonnumeric data, only the following formula options are supported:

Blank Text

Count

Count Distinct
Apply a Custom Formula
Click Define Custom Formula to define your own formula for a component. The Function dialog enables you to define Basic Math, Context, and Statistical functions in the layout.
The following figure shows the Function dialog:
About the Basic Math Functions
When you click one of the basic math functions, you are prompted to define the appropriate parameters for the function. You can enter a constant value, select a field from the data, or create a nested function to supply the value.
In the Function dialog, clicking the Multiplication function displays prompts to enter the multiplicand and the multiplier. The example shows that the multiplicand is the value of the Amount Sold field. The multiplier is the constant value.
About the Statistical Math Functions
When you click one of the statistical math functions you are prompted to define the appropriate parameter for the function. You can select a field from the data, or create a nested function to supply the values.
In the following figure, clicking the Average function displays prompts for you to specify the source of the values for which to calculate the average.
Apply a Custom Formula: Examples
Follow these examples to understand custom formula.
Example 31 Example 1: Subtraction
The following figure shows data for Revenue and Cost for each Office:
Using a custom formula, you can add a column to this table to calculate Profit (Revenue  Cost).

Add another numeric data column to the table. For example, drag another instance of Revenue to the table, as shown in the following figure:

With the table column selected, click Define Custom Formula.

In the Function dialog select Subtraction from the list, as shown in the following figure. Because the source data for the column is Revenue, by default the Minuend and the Subtrahend both show the Revenue element.

Select Subtrahend, then in the Parameter region, select Field and choose the Cost element, as shown in the following figure:
The dialog is updated to show that the formula is now Revenue minus Cost, as shown in the following figure:

Click OK to close the dialog.

The table column displays the custom formula. Edit the table column header title, and now the table has a Profit column, as shown in the following figure:
Example 32 Example 2: Nested Function
This example uses a nested function to create a column that shows Revenue less taxes.

Add another numeric data column to the table. For example, drag another instance of Revenue to the table, as shown in the following figure:

With the table column selected, click Define Custom Formula.

In the Function dialog select Subtraction from the list. Because the source data for the column is Revenue, by default the Minuend and the Subtrahend both show the Revenue element, as shown in the following figure:

Select Subtrahend, then in the Parameter region, select Nested Function and click Edit, as shown in the following figure.
A second Function dialog is displayed to enable you to define the nested function. In this case the nested function is Revenue times a constant value (tax rate of .23), as shown in the following figure:

Click OK to close the dialog. The primary Function dialog now shows the nested function as the source of the subtrahend, as shown in the following figure:

Click OK to close the Function dialog. The table column displays the custom formula. Edit the table column header label, and now the table displays the custom function, as shown in the following figure: