# Understanding the Poisson distribution

Let $P(x,u) = \dfrac{e^{-u} u^x}{x!}$ be a random variable. I understand the $u$ is the mean average of success, and $x$ is the random variable. So, how come when I assign $x=x$ $P(x,u)$ is significantly lower then $1$? If I sell two cars per day on average, my chances of selling two cars tomorrow should be pretty good right? Instead I got $P(2,2) = 0.2706$.

Would anyone care to explain? Thanks!

P.S. I was looking for a guide on how to write mathematical symbols here, but I couldn't find anything. Any links provided would be helpful.

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