Explanation:
Box 1: CALCULATE
CALCULATE rvaluates an expression in a modified filter context.
Box 2: DIVIDE
As a data modeler, when you write a DAX expression to divide a numerator by a denominator, you can choose to use the DIVIDE function or the divide operator (/ - forward slash).
When using the DIVIDE function, you must pass in numerator and denominator expressions.
Box 3: ALLSELECTED
ALLSELECTED removes context filters from columns and rows in the current query, while retaining all other context filters or explicit filters.
The ALLSELECTED function gets the context that represents all rows and columns in the query, while keeping explicit filters and contexts other than row and column filters. This function can be used to obtain visual totals in queries.
Example:
measure 'Reseller Sales'[Reseller Visual Total]=calculate(sum('Reseller Sales'[Sales Amount]), ALLSELECTED()) Reference:
https://docs.microsoft.com/en-us/dax/allselected-function-dax