I have written following script every time when I am asked by our team leaders or managers that how many rows are there in any particular table or sometime I am even asked which table has highest number of rows. Being Sr. Project Manager, sometime I just write down following script myself rather than asking my developers.
This script will gives row number for every table in database.
SELECT OBJECT_NAME(OBJECT_ID) TableName, st.row_count
FROM sys.dm_db_partition_stats st
WHERE index_id < 2
ORDER BY st.row_count DESC
Reference : Pinal Dave (http://blog.SQLAuthority.com)