What does n choose k mean?

My favorite proof of the n choose k formula!

What is n choose k? || formula, examples, Pascal's triangles

[Combinatorics] - What is N Choose K?

n choose k

Sum of n CHOOSE k (Nice identity!)

N Choose K

Fun Facts on N Choose K Binomials

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How to choose k for k-Means?

P1: 3 choose 1, n choose k problem

Factorials and Combinatorics : n choose k

Determining the Content of N choose K Subsets

How to use 'n choose k'

Factorials, PERMUTATIONS & Combinations | solving n-choose-k problems

Combinatorial Results: N choose k

14.3 The Binomail Theorem n choose k

p13.6.2 computing n choose k

Binomial Theorem, prove n choose k = n!/(k!(n-k)!)

Comparing NChooseK Algorithms - 3 of 4