Operand data type date is invalid for subtract operator.

CREATE FUNCTION Salman( @Date  date )
RETURNS TABLE
AS
RETURN
(

SELECT TOP 1000 [ID]
      ,[Name]
      ,[LastDate]
      ,[Rule]
      ,[CoA]
  FROM [Scheduling_Employee].[dbo].[Group]
  where ([LastDate]-@Date)%[Rule]=0
)
GO