## Enter your n and r values below:

<-- Enter (n)
<-- Enter (r)

Evaluate the combination:

8C4

##### Combination Definition:

A unique order or arrangement

##### Combination Formula:

 nCr  = n! r!(n - r)!

where n is the number of items
r is the unique arrangements.

##### Plug in n = 8 and r = 4

 8C4  2 8! 4!(8 - 4)!

##### Factorial Formula:

n! = n * (n - 1) * (n - 2) * .... * 2 * 1

##### Calculate the numerator n!:

n! = 8!

8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

8! = 40,320

##### Calculate (n - r)!:

(n - r)! = (8 - 4)!

(8 - 4)! = 4!

4! = 4 x 3 x 2 x 1

4! = 24

##### Calculate r!:

r! = 4!

4! = 4 x 3 x 2 x 1

4! = 24

##### Calculate 8C4

 8C4  = 40,320 24 x 24

 8C4  = 40,320 576

8C4 = 70

8C4 = 70
##### How does the Permutations and Combinations Calculator work?
Free Permutations and Combinations Calculator - Calculates the following:
Number of permutation(s) of n items arranged in r ways = nPr
Number of combination(s) of n items arranged in r unique ways = nCr including subsets of sets
This calculator has 2 inputs.

### What 2 formulas are used for the Permutations and Combinations Calculator?

nPr=n!/r!
nCr=n!/r!(n-r)!

For more math formulas, check out our Formula Dossier

### What 4 concepts are covered in the Permutations and Combinations Calculator?

combination
a mathematical technique that determines the number of possible arrangements in a collection of items where the order of the selection does not matter
nPr = n!/r!(n - r)!
factorial
The product of an integer and all the integers below it
permutation
a way in which a set or number of things can be ordered or arranged.
nPr = n!/(n - r)!
permutations and combinations