SSRS Subreport: Record count of Subreport from Main report

Method One:
I think that you can try to add the same subreport datasets to the main report, and use the same parameters to filter the dataset records. After that, you can use the following expression to get the number of rows: 
=CountRows(“DataSet2”) and  
=CountRows(“DataSet3”)

SSRS: Report parts

SSAS: Definition of SSAS

SSRS Report: Date addition, subtraction

Scenario: 
I want to subtract 7 days from the date I choose in the date parameter

Solution:
In the expression write=Dateadd("d",-7,Parameters!RefDate.Value)

Scenario:
I want just change the year part of the Date field. Changing 365 days does not work because of the leap year.

Solution:
SQL Command:

UPDATE dbo.TableToUpdate
  SET [Date Column] = DATEADD(YEAR, -2, [Date Column]);

SSRS Command: