Need help to count non blanks in a measure

[MegaOctane1]

I have three tables.

Table 1 CustomerMaster:

CustomerNumber	Customer Name
100	Apple
101	Microsoft

Table 2, Open invoices in ERP:

CustomerNumber	Invoice	Amount
100	3	1000
100	4	2000
101	5	3000

Table 3, Open invoices InvoicePartner:

CustomerNumber	Invoice	Amount
100	3	1000
101	5	3000

Relationship is Table 1 CustomerNumber to Table 2 CustomerNumber, and Table 1 CustomerNumber to Table3 CustomerNumber

I have a measure to calculate the difference of these two tables. 
Measure is:

Difference = VAR _DIFF_CHECK = [SUM ERP]-[SUM InvoicePartner] Return IF(_DIFF_CHECK<>0, _DIFF_CHECK)

it returns this:

CustomerNumber	Difference
100	2000
101	0

How can i create a card visual/measure to say that number of customers with difference is 1?

i am not able to do a countIF(Difference<>0)

[lbendlin · Accepted solution]

I would propose a different approach.

see attached.