Math Help - Sum of Factorial

1. Sum of Factorial

need to find the sum of (1/n!)
from n= 1 to infinity

2. $\sum_{n=1}^\infty \frac{1}{n!} = \sum_{n=1}^\infty \frac{1^n}{n!} = (\sum_{n=0}^\infty \frac{1^n}{n!}) - 1 = e^1 - 1 = e - 1$

3. thank alout