SOLUTION: How many four-letter permutations can be formed from the first seven letters of the alphabet?

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Question 1118861: How many four-letter permutations can be formed from the first seven letters of the alphabet?
Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
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7*6*5*4 = 840 ways. 

Any of 7 letter in the 1-st position.                  7 opportunities.

Any of remained 6 letters in the 2-nd position.        6 opportunities

Any of remained 5 letters in the 3-rd position.        5 opportunities.

Any of remained 4 letters in the 4-th position.        4 opportunities.