Binomial Coefficient Calculator

Calculate combinations (n choose k) using the binomial coefficient formula

Calculate Binomial Coefficient

The total number of items in the set (0 ≤ n ≤ 1000)

The number of items to choose from the set (0 ≤ k ≤ n)

Binomial Coefficient Result

C(0,0) = 1
"0 choose 0" = 1
Alternative Notation
C(0,0)
(0 choose 0)
nCr on calculator
Interpretation
Number of ways to choose 0 items from 0 items where order doesn't matter

Formula: C(n,k) = n! / (k! × (n-k)!)

Symmetry property: C(0,0) = C(0,0)

Pascal's Triangle Row 0

1

The highlighted value is C(0,0) = 1

Step-by-Step Solution

Step 1: Formula

The binomial coefficient formula is:

C(0,0) = n! / (k! × (n-k)!) = 0! / (0! × (0)!)

Step 2: Special Case

When k = 0, C(n,0) = 1 (there is exactly one way to choose 0 items)

C(0,0) = 1

Common Examples

C(4,2) = 6
Ways to choose 2 items from 4: {AB, AC, AD, BC, BD, CD}
C(5,0) = 1
Only one way to choose nothing from any set
C(6,1) = 6
6 ways to choose 1 item from 6 items
C(10,2) = 45
45 ways to choose 2 items from 10
C(52,5) = 2,598,960
Poker hands: 5 cards from 52-card deck
C(n,n) = 1
Only one way to choose all items

Quick Reference

Notation
C(n,k), (n choose k), nCr
Formula
n! / (k! × (n-k)!)
Symmetry
C(n,k) = C(n,n-k)
Edge Cases
C(n,0) = C(n,n) = 1

Calculator Tips

Order doesn't matter in combinations

k cannot be greater than n

Both n and k must be non-negative integers

Use symmetry for large values of k

Applications

Probability
Calculating probability in binomial distributions
Statistics
Sampling without replacement
Gaming
Poker hands, lottery combinations
Algebra
Binomial theorem expansions

Understanding Binomial Coefficients

What are Binomial Coefficients?

Binomial coefficients, denoted as C(n,k) or "n choose k," represent the number of ways to choose k items from a set of n items where the order of selection doesn't matter. They are fundamental in combinatorics, probability theory, and algebra.

Key Properties

  • Symmetry: C(n,k) = C(n,n-k)
  • Edge cases: C(n,0) = C(n,n) = 1
  • Pascal's identity: C(n,k) = C(n-1,k-1) + C(n-1,k)
  • Sum: ∑C(n,k) = 2ⁿ for k=0 to n

Combinations vs. Permutations

Combinations (C)
Order doesn't matter
Selecting items
Example: Choosing a team
Permutations (P)
Order matters
Arranging items
Example: Race positions

Real-World Examples

Poker: C(52,5) = 2,598,960 possible hands
Lottery: C(49,6) = 13,983,816 combinations
Teams: C(20,4) = 4,845 ways to form groups of 4

Binomial Theorem Connection

Binomial coefficients appear in the binomial theorem, which describes the expansion of powers of binomials:

(a + b)ⁿ = ∑[k=0 to n] C(n,k) × aⁿ⁻ᵏ × bᵏ

For example: (x + y)³ = C(3,0)x³ + C(3,1)x²y + C(3,2)xy² + C(3,3)y³ = x³ + 3x²y + 3xy² + y³