20! = 20 x 19 x 18 x 17 x 16 x 15 x 14 x 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
20! = 2,432,902,008,176,640,000
Calculate (n - r)!:
(n - r)! = (20 - 3)!
(20 - 3)! = 17!
17! = 17 x 16 x 15 x 14 x 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1
17! = 355,687,428,096,000
Calculate r!:
r! = 3!
3! = 3 x 2 x 1
3! = 6
Calculate 20C3
20C3 =
2,432,902,008,176,640,000
6 x 355,687,428,096,000
20C3 =
2,432,902,008,176,640,000
2,134,124,568,576,000
20C3 = 1,140
You have 2 free calculationss remaining
Excel or Google Sheets formula:
Excel or Google Sheets formula:=COMBIN(20,3)
What is the Answer?
20C3 = 1,140
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?
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