To do basic calculation and data analysis on data in POWER pivot we use Data Analysis Expression (DAX).It is formula language to compute calculated column and calculated field. 

• Dax works on column values
• Dax can not modify or insert data
• We can CALCULATE calculated column and measures but we can not calculate rows using dax

Sample DAX formula syntax:

For the measure named Total SALES, calculate (=) the SUM of values in the [SalesAmount ] column in the Sales table.

A- Measure Name

B- equal sign - indicate beginning of formula

C- DAX Function

D- Parenthesis for Sum Function

E- Referenced Table

F- Referenced column name

To do basic calculation and data analysis on data in power pivot we use Data Analysis Expression (DAX).It is formula language to compute calculated column and calculated field. 

Sample DAX formula syntax:

For the measure named Total Sales, calculate (=) the SUM of values in the [SalesAmount ] column in the Sales table.

A- Measure Name

B- equal sign - indicate beginning of formula

C- DAX Function

D- Parenthesis for Sum Function

E- Referenced Table

F- Referenced column name