The number of 4 letter words (with or without meaning) that can be formed from the eleven letters of the word “EXAMINATION” is __________

EXAMINATION 2 N,2 A,2I,E,X,M,T,O Case I    All are different so P4   8=8!4!=8.7.6.5=1680 Case II 2 same and 2 different so C1   3·C2   7·4!2!=3.21.12=756 Case III   2 same and 2 same so C2   3·4!2!.2!=3.6=18 Total =1680+756+18=2454