DATEADD : Used for time intelligence, such as calculating "Year-Over-Year" growth by shifting dates.
CALCULATE : The most powerful function, used to modify the filter context of a calculation. Practical PowerPivot & DAX Formulas for Excel
RANKX : Automatically ranks items (like products or sales reps) based on a specific value. Practical PowerPivot & DAX Formulas for Excel 2010 DATEADD : Used for time intelligence, such as
SUMX : An "iterator" function that performs a calculation row-by-row before summing the results. DATEADD : Used for time intelligence