There is a set of functions that commonly used in many DAX expressions. These are functions that work as a filter or iterator or even Calculate. In this module, you will learn what is an Iterator and how it can be used in a measure. You will also learn about filter functions such as ALL or Filter and how they can work combined with an iterator function. You will also learn examples of conditional sum implemented using the functions mentioned in this module. at the end of the module, you will also learn about Calculate which is one of the most common and powerful functions used in DAX.