Data Analysis Expressions (DAX) functions form the calculation engine of Power BI reports. They are used to create measures, calculated columns and calculated tables that determine how totals, ratios, comparisons, and time based metrics are computed across dashboards. In this 3 hour training, learners focus on the DAX functions most commonly applied in business reporting and understand how row context and filter context directly influence calculation results. The session emphasizes correct function usage to prevent inaccurate totals and maintain consistency in analytical reporting.