Hi Josepatwentysix
I'm not sure if I fully understood your question, but I'll try to answer the question.
You have to create 3 measures in PBI Desktop.
1. Measure:
FirstMeasure = sum(Tabelle1[A])
2. Measure:
SecondMeasure = sum(Tabelle1[B])
Difference Measure:
Difference = [FirstMeasure] - [SecondMeasure]
Greetings
Hp Pfister
Measure A: calculate something
Measure B: calculate something
Measure Difference: = A - B