How many words can be formed from the letters of the word ‘computer’ if each letter is to be used once?

##8! = 40320## (assuming any sequence of the ##8## given letters is considered a “word”)
There are 8 distinct letters in “computer
In forming a “word”
##color(white)(“XXX”)##There are ##8## choices for the first letter.
For each choice of a first letter
##color(white)(“XXX”)##there are ##7## choices for the second letter.
For each choice combination of a first and second letter
##color(white)(“XXX”)##there are ##6## choices for the third letter.
…and so on, resulting in
##color(white)(“XXX”)8xx7xx6xx…xx2xx1 = 8!## ways of selecting the letter order.