# Overview

Expressions in a report can contain functions. Functions are predefined formulas that perform calculations by using specific values, called arguments, in a particular order. Functions can be used to perform simple or complex calculations. The structure of a function begins with the function name, followed by an opening parenthesis, the arguments for the function separated by commas, and a closing parenthesis.

Arguments can be field references, numbers, text, and logical values such as TRUE or FALSE. Arguments can also be constants, formulas, or other functions. The arguments that you enter must produce a valid value for that argument. For example, if the formula is multiplying two integers, the result cannot be a text string.

Telerik Reporting provides many built-in functions and also lets you create user-defined functions. The categories of built-in functions are listed on this page.