Question

Calcule.

a) 4!

b) 7!

c) 5 ∙ 6!

d) 11!/9!

e) 10!/6!

f) 27!/2!25!

Answer 1

a)

$4! = 4 . 3 . 2 . 1 => 24$

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b)

$7! = 7.6.5.4.3.2.1 => 5040$

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c)

5 . 6!

5 . 6 . 5 . 4 . 3 . 2 . 1 => 5 . 720

=> 3600

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d)

$\dfrac{11!}{9!} \\ \\ \\ \dfrac{11 . 10, \not 9!}{\not 9!} \\ \\ \\ 11 . 10 => 110$

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e)

$\dfrac{10!}{6!}\\ \\ \\ \dfrac{10. 9 . 8 . 7 . \not 6 !}{\not 6!}\\ \\ \\ 10. 9 . 8 . 7 => 5040$

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$\dfrac{27!}{2! . 25!}\\ \\ \\ \dfrac{27. 26 . \not 25!}{2! .\not 25!}\\ \\ \\ \dfrac{27. 26}{2}\\ \\ \\ \dfrac{702}{2} \ => 351$