Airtel user cheaper subscription activating code

plan                         Data v.  P.        CODE
android bundle.      1GB.  N1000.  *496#
android bundle     2GB.   N2000.  *437#
android 4.5bundle. 4.5GB. N2,500 *437*1#
android bundle.        9GB.       N3,500. *438*1#

how to check data balance
*123*9#
or *140#