Permutation & Combination Calculator (nPr, nCr)

Results

Step log

Steps are hidden. Turn on “Show steps” to view them.

Teacher notes

• Combination: nCr = n! / (r!(n-r)!). Symmetry C(n, r) = C(n, n-r) lets you halve the work by using k = min(r, n-r).
• Permutation: nPr = n! / (n-r)!. Remember P(n, 0) = 1 and P(n, n) = n! for boundary checks.
• Factorial: n! = 1 × 2 × … × n with 0! = 1. Reinforce the base case when reviewing recurrence proofs.
• When inputs blow past the Exact limit (roughly n = 10,000), switch to Approx so learners still see the order of magnitude and digit count.
• This tool is for educational use only. Always double-check final answers before grading or publishing materials.

FAQ

İlgili hesaplayıcılar

• Pascal's triangle & binomial expansion (with steps)

How it's calculated

• Combinations nCr and permutations nPr with factorials.
• For large n uses logs/approximation to avoid overflow.
• Share URL preserves n and r.