免费阶乘计算器
计算任意正整数的阶乘n!，适用于排列组合计算。
Factorial Val
5,040
N Minus 1 Factorial720
公式
How to Calculate a Factorial
Formula
n! = n × (n-1) × (n-2) × ... × 2 × 1
Special cases:
Factorials grow extremely fast. 10! = 3,628,800 and 20! = 2,432,902,008,176,640,000.
计算示例
Calculate 7!
- 017! = 7 × 6 × 5 × 4 × 3 × 2 × 1
- 02= 42 × 5 × 4 × 3 × 2 × 1
- 03= 210 × 4 × 3 × 2 × 1
- 04= 840 × 3 × 2 × 1
- 05= 2520 × 2 × 1
- 06= 5040
常见问题
What is a factorial?
A factorial (written as n!) is the product of all positive integers from 1 to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120.
Why is 0! equal to 1?
By convention and mathematical consistency, 0! = 1. This is needed for formulas like combinations to work correctly: C(n,0) = n! / (0! × n!) = 1.
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