# Common functions The **Common** category contains functions that handle page numbering, and a generic OpenFormula feature that you can use to create your own custom function. | Function Name | Purpose | | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **Open Formula** | Enables you to create your own custom OpenFormula function using the built-in Formula Editor. This function will run according to its placement in the report. If you need a custom function to run before all other report actions, use the **Open Formula** function in the **Advanced** category instead. | | **Page** | Counts the number of pages rendered thus far in a report. | | **Total Page Count** | Lists the total number of pages in the rendered report. | | **Page of Pages** | Prints the current page number in comparison to the total number of pages in the rendered report. | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.pentaho.com/pba-report-designer/10.2-report-designer/function-reference/common-functions.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.