SUMX/Calculate Table on data range

Hi Jerry-P4P 

I'd recommend unpivotting the data in Power Query. 

That will get you a table with a single Date column (which you currently have as separate columns) with a corresponding Amount column.

Your measure is then

Total Amount = SUM(Table[Amount])

Hi What Paul said is good.

One minor add on is you will want to click the top of each text column in PQ then choose for the drop down "Unpivot Other Columns"

OR

Highlight all those data columns only and "Unpivot Columns". Then you just have to sum up one column to get your total as  suggested.