Find the number of combinations and permutations of 4 letters taken from the word ‘EXAMINATION’.

Explanation

Case 1

4 letters=0

Case 2

3 letters=0

Case 3

2 letters=`.^3C_2*(4!)/(2!2!)`

Case 4

1 letters=`.^3C_2*(4!)/(2!2!)+.^3C_1*.^7C_2*(4!)/(2!)+.^8C_4*4!`.