Please, read my comment to the question.
Date is a date and nothing else!
If you want to add date, use proper variable type:
DECLARE @fromdate DATE = '2015/10/01'
If MS SQL Server can't recognize such of format, use:
SET DATEFORMAT[
^] command.
SET DATEFORMAT ymd;
DECLARE @fromdate DATE = '2015/10/01'
For further information, please see:
CAST and CONVERT (Transact-SQL)[
^]
Date and Time Data Types and Functions (Transact-SQL)[
^]