# Combinations

## #Combinations #Basics

Choose X from N is

$$ C_N^X = \frac{N!}{ X! (N-X)! } $$

Published:
by Lei Ma;

## Table of Contents

**Current Ref:**

- cards/math/combinations.md

Choose X from N is

$$ C_N^X = \frac{N!}{ X! (N-X)! } $$

Published:
by Lei Ma;

**Current Ref:**

- cards/math/combinations.md