show delta value

[tangutoori]

Prev Name	Current name
123a	abc
456b	def
ebom	$ values
abc	120
def	100
123a	50
456b	80
789c	90

am havign two tables.  change info, part name previous is changed to current values. secodn table have $ values for the old anf new parts. how can i show delta if i select current part. 

if i select abc in drop down list i should get 70 as result.

abc
Prev Name	Current name	Delta
123a	abc	70

[Ahmedx]

and if you want to select a name in the slicer and show delta on the map, then you need to write the measure as follows:

[Ahmedx · Accepted solution]

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end.
https://1drv.ms/u/s!AiUZ0Ws7G26Rhj3Hjd6fYbfCxFGh?e=4vLMgM