## Algebra 2 (1st Edition)

$0! = 1$ as a factorial signifies the multiplication of all natural numbers less than or equal to the argument. Another way to look at this is $(n)! = (n-1)! * n$ thus $1! = 0! * 1$ and $1! =1$. Solving for $0!$ or $0! = 1/1 = 1$