The Formula Builder is a powerful visual tool for building and editing the variable calculations for the model.

Variable Properties
Name  The name of the variable. This is the name that will be displayed in the Formula Builder for any references to this variable. 
Data Type  The type of data the variable is expected to return from its formula. The system will perform validations to ensure that the formula produces a result of this type. 
Display Precision  The display precision affects how results of this variable get displayed in reports. It has no impact on the precision of calculations performed during runtime, however. 
Aggregation  This option will only be available on Product Variables. This sets if and how the results of this variable result should be aggregated across a whole product. See below for more details on aggregation. 
Time Indexed?  Indicates if this is a timeindexed variable. Check this box if the formula should be run at each time index of the projection. If it only needs to be calculated once for the entire run, then leave this box unchecked. Note: Nontimeindexed variables cannot use the results of timeindexed variables in their formula. 
Scales on Purchase or Sale  This option will only be available on Asset type Product Variables. This controls the behavior for how the variable will be treated upon the sale of an asset. 
Aggregation (Product Variables Only)
None  The results will not be aggregated. The results of this variable will not be available at other calculation levels. 
Sum  The result of the calculation for all model points will be summed across the product. 
Average  The average of the calculation result will be calculated for the product by summing across all model point results and then dividing by the total number of inforce model points. 
First Value  Only a single value from the first model point will be saved as the total Product result. This can be useful if there is a value that is identical across all model points within a product. However, it is important to note that the first value will be the first value that is calculated at runtime, which may or may not be the first model point in numerical order due to the nature of parallel processing in Slope. 
Formula Editor
The Formula Component Selector is used as the starting point for building all formulas. Clicking on this icon will open the Component Menu where you can select from all the Formula Types available. Clicking on any icon will append the new formula component to the formula at the location of the Formula Component Selector.
Operator Selector
The Operator Selector is used to choose an Operator within a formula involving two operands. When a new Component is added via the Formula Component Selector, a new Component will be added to the right of the existing Components within the formula and an Operator Selector is added to the left of the new Component. When a new Component is added, the Operator defaults to addition ("+") and can be edited. If you click and drag a Component within the formula editor or you insert a new Component between two existing Components, the Operator will be set to blank and an Operator will need to be selected.
Clicking on the Operator Menu within the Operator Selector will bring up the following Operator icons:
Addition  
Subtraction  
Multiplication  
Division  
Exponent  
Modulus (Remainder)  
Formula insertion. A Component will be added between two existing Components populated with a Formula Component Selector. A blank Operator Selector will be added to the right of the Component. Note that if the new blank Component or the new blank Operator is not populated, an error message will appear and the formula cannot be saved. 