use permutations which is also the slot meathod so exg
if you have the letters abc, then how many ways can you arrangge them with no repreats?
3 choices for the 1st slot
2 choices for the 2nd slot since 1 was used in 1st slot
3 choices for 3rd slot since 2 were used in previous slots so basically 3 times2 times 1 or 6
in this case of HEXAGON
7 letters so
7 times 6 times 5 times 4 times 3 times 2 times 1=answer=5040 ways