Hello Sai,
It depends on a setting. Follow the below steps to get it resolved.
1. Goto 'System' in the menu bar.
2. Click on 'User Profile'.
3. Click on 'Own Data'.
4. Separate window will open. There you will find 3 tabs ==> Address, Defaults, Parameters.
5. Goto 'Defaults'. There you can find 'Decimal Notation' field.
6. Change it according to your requirement.
Regards,
Imran.