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

$\begin{array}{l}\text{ EXAMINATION }\\ 2 \mathrm{N},2 \mathrm{A},2\mathrm{I},\mathrm{E},\mathrm{X},\mathrm{M},\mathrm{T},\mathrm{O}\\ \text{ Case I } \text{ All are different so }{}^{8}P_4=\frac{8!}{4!}=8.7.6.5=1680\\ \text{ Case II }2\text{ same and }2\text{ different so }{}^{3}C_1·{}^{7}C_2·\frac{4!}{2!}=3.21.12=756\\ \text{ Case III } 2\text{ same and }2\text{ same so }{}^{3}C_2·\frac{4!}{2!.2!}=3.6=18\\ \text{ Total }=1680+756+18=2454\end{array}$