Question 764789
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"algorithm" has 9 unique (non-repeating) letters.

From 9, a set of 7 letters can be chosen in "9 choose 7" or C(9,7) ways, which
is (9*8)/(1*2) or 36 ways.

Each of these 7-letter can be arranged in 7! (factorial 7, or 1*2*3*4*5*6*7) ways.

So the total number of different words = 36 * 7! = 36 * 5040 = 181440.

:)
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