12 Combinations of 3

12 Combinations of 3

Evaluate the combination:

12C3

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 = 12 and r = 3
12C3  2  12!
  3!(12 - 3)!

Factorial Formula:

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

Calculate the numerator n!:

n! = 12!

12! = 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

12! = 479,001,600

Calculate (n - r)!:

(n - r)! = (12 - 3)!

(12 - 3)! = 9!

9! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

9! = 362,880

Calculate r!:

r! = 3!

3! = 3 x 2 x 1

3! = 6

Calculate 12C3
12C3  =  479,001,600
  6 x 362,880

12C3  =  479,001,600
  2,177,280

12C3 = 220



Excel or Google Sheets formula:

=COMBIN(12,3)

What is the Answer?

12C3 = 220

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

Example calculations for the Permutations and Combinations Calculator

Permutations and Combinations Calculator Video


James H. Sterling
Author

James H. Sterling

James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.